Which one of the following equations is dimensionally correct?
v^2=ax
f the average velocity is non-zero over some time interval, does this mean that the instantaneous velocity is never zero during the same interval?
no
f the velocity of a car is non-zero, can the acceleration of the car be zero?
yes
On a position versus time graph, the slope of a line between two points on the graph is?
the average velocity
On a velocity versus time graph, the slope of a tangent line to the graph is ?
the instantaneous acceleration
If a particle has a constant velocity, must it have a constant speed?
no
f a particle has a constant speed, must it have a constant velocity?
yes
A car is driven from town A to town B. When it arrives at B the magnitude of its displacement from A is
Always less than or equal to the distance it traveled.
At any moment the slope of the velocity vs time graph of a body moving in a straight line is its
None of the above
The area under a curve plotted on a velocity versus time graph represents ?
Displacement
You throw a ball straight up into the air. After it leaves your hand, at what point in its flight does it have the maximum value of acceleration?
Its acceleration is constant everywhere
You drop a rock off a bridge. When the rock has fallen 4 m, you drop a second rock. As the two rocks continue to fall, what happens to their velocities?
Both increase at the same rate
Which of these is NOT a scalar?
Velocity
Two vectors have unequal magnitudes. Can their sum be zero?
No, never.
A vector A is added to a vector B. Under what conditions does the resultant vector A+ B have greatest magnitude?
When A and B are parallel and in the same direction.
A rock is dropped out of the window of a moving car. At the same time a ball is dropped from rest from the same height. Which will reach the ground first? (Neglect air resistance.)
Both will reach at the same time
A projectile is launched from the ground at an angle of 30 0 . At what point in its trajectory does this projectile have the least speed?
At the highest pointin its flight
A car is travelling in a circle with a constant speed. Which statement is true?
The car has changing velocity and changing acceleration.
A net force F acts on an object. This means
the object may be moving in any direction.
A net force F acts on an object. This means A net force F acts on an object. This means
the object must be acceleration in the direction of
Consider a person standing in an elevator that is accelerating downward. Compared to the magnitude of the weight of the person, the magnitude of the upward normal force excerted by the elevator floor on the person is
Smaller
A small sports car collides head - on with a massive cement truck. Which vehicle experiences the greater force due to the collision
Both experience the same magnitude of force during the collision.
Which vehicle in the collision above experiences the greater magnitude of acceleration during the collision?
the car
An object of mass M on a horizontal surface is pushed with a horizonta force F. The coefficient of static friction is μ s . The object does not move. The magnitude of the static friction force on the object is
An object of mass M on a horizontal surface is pushed with a horizonta force F. The coefficient of static friction is μ s . The object does not move. The magnitude of the static friction force on the object is
When you climb up a rope, the first thing you do is pull down on the rope. How do you manage to go up the rope by doing that
the rope actually pulls you up
You tie a rope to a tree and you pull on the rope with aforce of 100 N. What is the tension in the rope
100 N
You and a friend can each pull with a force of 20N. If you want to rip a rope in half, what is the bext way
tie the rope to a tree, and you both pull from the same end
A piece of mud flies off the rim of a bycicle wheel. In what direction will it be going immediately after leaving the wheel? (Ignore gravity in this short time inter
On a line at a tangent to the edge of the wheel.
Is it possible to do work on an object that remains at res
no
A box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction
Friction does negative work
A ball tied to a string is being whirled around in a circle. What can you say about the work done by ten
Tension does no work at all
A box is being pulled up a rough incline by a rope connected to a pulley. How many forces are doing work on the box? Ignore air resistance/fricti
three forces
What force is responsible for holding a car in an
unbanked
curve
The force of friction
What force is responsible for holding a car in a
banked
curve with frictio
A combination of the force of friction and the horizontal component of the normal force.
Which statement about work is true?
Only the component of a force parallel to the displacement does work.
A box weighing 100 N is lifted 1.5 m vertically, and is then held there. How much work is being done in holding the box in the elevated position
No work is being done
How much work was done by the lifting force as the box weiging 100 N was raised by 1.5 m?
150 J
A women pulls a crate up a rough incline plane at a constant velocity. Which statement is false
The work done by gravity is zero
An apple falls from rest through the air (air resistance is present) gaining 10 J of kinetic energy. How much gravitational energy did the apple lose
more than 10 J
You slam on your brakes in a panic and skid a certain distance down a straight and level road. If you had been travelling twice as fast, what distance would the car have skidded under the same conditions?