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Gravity
Chapter 4-6
Terms in this set (56)
A boy throws a ball at an initial velocity of 26 m/s at an angle of 20o above the horizontal. How high above the projection point is the ball after 1.4 s?
2.8 m
A boy kicks a football with an initial velocity of 20 m/s at an angle of 25o above the horizontal. The acceleration of the ball while it is in flight is
-9.8
A projectile is launched with an initial velocity of 80 m/s at an angle of 30o above the horizontal. Neglecting air resistance, what is horizontal component of the projectile's acceleration?
0 m/s2
A boy kicks a football with a certain initial velocity at an angle 20o above the horizontal. In 2.0 seconds, the ball reaches at its highest point in its trajectory. What is the initial velocity of the ball?
57 m/s
The horizontal and vertical components of the initial velocity of a football are 24 m/s and 7 m/s respectively. What is the initial velocity of the football?
25 m/s
A bullet is fired from ground level with a speed of 150 m/s at an angle 30.0o above the horizontal at a location where g = 10.0 m/s2. What is the horizontal component of its velocity when it is at the highest point of its trajectory?
130 m/s
A bullet is fired from ground level with a speed of 150 m/s at an angle 30.0o above the horizontal at a location where g = 10.0 m/s2. What is the vertical component of its velocity when it is at the highest point of its trajectory?
0
A bullet is fired from ground level with a speed of 150 m/s at an angle 30.0o above the horizontal at a location where g = 10.0 m/s2. What is the vertical component of its velocity after 4 seconds
35 m/s
A bullet is fired with a certain velocity at an angle above the horizontal at a location where g = 10.0 m/s2. The initial x and y components of its velocity are 86.6 m/s and 50.0 m/s respectively. How long does it take before the bullet gets to the highest point of its trajectory?
5.0
A hockey puck slides off the edge of a table with an initial velocity of 20 m/s. The height of the table above the ground is 2.0 m. What is the magnitude of the velocity of the puck just before it touches the ground?
20.95 m/s
A person throws a ball horizontally from the top of a building that is 22.0 m above the ground level. The ball lands 100 m down range from the base of the building. What was the initial velocity of the ball?
47.2 m/s
A ball is thrown horizontally with an initial velocity of 40 m/s from a height of 10 m. How long will it take for the ball to touch the ground? Use g = 10 m/s2
1.4 s
A ball is thrown horizontally with an initial velocity of 20.0 m/s from the edge of a building of a certain height. The ball lands at a horizontal distance of 82.0 m from the base of the building. What is the height of the building?
82.3 m
A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 30o above the horizontal. What is the horizontal component of its velocity just before it hits the ground?
17.3 m/s
A boy kicks a football with an initial velocity of 20 m/s at an angle of 30o above the horizontal. What is the vertical component of its velocity at the highest point of its trajectory?
0
For which value of is the range of a projectile fired from ground level a maximum?
45
A ball is thrown at an angle 45o above the horizontal with an initial velocity of 20 m/s. What is the total time of flight of the ball before it hits the ground?
2.88s
A ball is thrown at an angle 40.0o above the horizontal with an initial velocity of 22.0 m/s. What is the range of the ball?
48.6 m
A bullet is fired from ground level with a speed of 150 m/s at an angle 30.0o above the horizontal at a location where g = 10.0 m/s2. What is the range of the bullet (horizontal distance from the starting point to the point where it lands on the ground)?
1949.6 m
A projectile is shot from the edge of a vertical cliff 60.0 m above the ocean. It has a speed of 100 m/s and is fired at an angle of 35.00 above the horizontal. How far from the foot of the vertical cliff does the projectile hit the water?
1037 m
An object is moving with constant velocity. Which of the following statements is true?
A) A constant force is being applied in the direction of motion.
B) There are no forces acting on the object.
C) The net force on the object is zero N.
D) There is no frictional force acting on the object.
The net force on the object is zero N.
A force of 120 N is applied to an object whose mass is 30 kg. The object's acceleration is
4.0 m/s2
A net force of 120 N is applied to a certain object. As a result, the object accelerates with an acceleration of 24.0 m/s2. The mass of the object is
5.0 kg
A 777 aircraft has a mass of 300,000 kg. At a certain instant during its landing, its speed is 27.0 m/s. If the braking force is 430,000 N, what is the speed of the airplane 10.0 s later?
12.7 m/s
What average net force is required to accelerate a car with a mass of 1200 kg from 0 to 27.0 m/s in 10.0 s?
3240 N
A truck is towing a car whose mass is one quarter that of the truck. The force exerted by the truck on the car is 6000 N. The force exerted by the car on the truck is
6000 N.
Two boxes, one more massive than the other, rest in contact with one another on a smooth, level floor. A horizontal force F pushes on one or the other of the boxes. The contact force between the boxes
A) is larger when F is applied to the more massive box.
B) is larger when F is applied to the less massive box.
C) is equal in both cases.
D) can be larger or smaller depending on the actual masses.
is larger when F is applied to the less massive box.
A 3.0-kg and a 5.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 3.0-kg box pushing it against the 5.0-kg box, and, as a result, both boxes slide along the floor. How large is the contact force between the two boxes?
20 N
A 3.0-kg and a 5.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 5.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How large is the contact force between the two boxes?
12 N
A 1200-kg car is pulling a 500-kg trailer along level ground. Friction is negligible. The car accelerates with an acceleration of 1.3 m/s2. What is the force exerted by the car on the trailer?
650 N
A 50.0-kg crate is being pulled along a horizontal, smooth surface. The pulling force is 10.0 N and is directed 20.0° above the horizontal. What is the acceleration of the crate?
0.188 m/s2
A 40.0-kg box is being pushed along a horizontal, smooth surface. The pushing force is 15.0 N directed at an angle of 15.0° below the horizontal. What is the acceleration of the crate?
0.362 m/s2
A person has a mass of 45 kg. How much does she weigh on the Moon, where g = 1.62 m/s2?
73 N
An astronaut weighs 99.0 N on the Moon, where the acceleration of gravity is 1.62 m/s2. How much does she weigh on Earth?
600 N
A 40.0-kg crate is being lowered by means of a rope. Its downward acceleration is 2.00 m/s2. What is the force exerted by the rope on the crate?
312 N
A flatbed truck is carrying a 20.0-kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?
3.92 m/s2
A flatbed truck is carrying a 20.0-kg crate up a sloping road inclined 15.0° above the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?
1.25 m/s2
A policeman investigating an accident measures the skid marks left by a car. He determines that the distance between the point that the driver slammed on the brakes and the point where the car came to a stop was 34.0 m. From a reference manual he determines that the coefficient of kinetic friction between the tires and the road under the prevailing conditions was 0.300. How fast was the car going when the driver applied the brakes? (This car was not equipped with anti-lock brakes.)
14.1 m/s
A 50.0-kg box is being pushed along a horizontal surface. The coefficient of kinetic friction between the box and the ground is 0.350. What horizontal force must be exerted on the box for it to accelerate at 1.20 m/s2?
232 N
A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 30.0° below the horizontal is applied to the box. The coefficient of static friction between the box and the surface is 0.400. What is the force of friction on the box?
217 N
A 50.0-kg block is being pulled up a 15.0° slope by a force of 250 N which is parallel to the slope, but the block does not slide up the slope. What is the minimum value of the coefficient of static friction required for this to happen?
0.260
A box slides down a 27.0° slope under its own weight. The coefficient of kinetic friction between the box and the slope is 0.350. What is the acceleration of the box?
1.39 m/s2
As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is
A) static friction.
B) kinetic friction.
C) a combination of static and kinetic friction.
D) It is impossible to tell what type of friction acts in this situation.
static friction.
The force of static friction f must be such that
The force of static friction f must be such that
The normal force F acting on the block must be such that
The normal force F acting on the block must be such that
A 30.0-kg crate is pulled along a horizontal floor by the ideal arrangement shown in Figure 6-2. The force F is 300 N. The coefficient of friction between the crate and the floor is 0.350. What is the acceleration of the crate?
1.57 m/s2
When a mass of 25.0 grams is suspended from a certain spring and lowered slowly until the spring stops stretching, the spring stretches 2.00 cm. What is the spring constant of the spring?
12.3 N/m
A mass of 40.0 grams is attached to a vertical spring with a spring constant k = 20.0 N/m and lowered slowly until the spring stops stretching. How much does the spring stretch?
0.0196 m
A mass of 3.0 kg rests on a smooth surface inclined 28° above the horizontal. It is kept from sliding down the plane by a spring attached to a wall. The spring is aligned with the plane and has a spring constant of 120 N/m. How much does the spring stretch?
12 cm
A 10-kg sign is held by two ropes as shown in Figure 6-3. What is the tension on rope A?
88 N
A 2 kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the magnitude of the net force on the ball?
100N
A baseball player is running to second base at 5.63 m/s. When he is 5.20 m from the plate he goes into a slide. The coefficient of kinetic friction between the player and the ground is 0.220. What is his speed when he reaches the plate?
3.04 m/s
When a mass of 25 g is suspended from a spring and lowered slowly until the spring stretches 2.00 cm. What is the spring constant of the spring?
12.3 N/m
A mass of 40.0 g is attached to a vertical spring with spring constant k = 20 N/m and lowered slowly until the spring sops stretching. How much does the spring stretch?
0.0196 m
A 2-kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the magnitude of the net force on the ball?
100 N
A 1000-kg car is moving at 30.0 m/s around a horizontal curve whose radius is 100 m. What is the magnitude of the frictional force required to keep the car from sliding?
9000 N
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