## 64 terms

### The re-creation of an event by comparing two situations in which all the factors are identical except one is called a?

controlled experiment

### A tentative scientific explanation which may or may not be rejected upon further experimentation is called a?

hypothesis

### An object accelerates when it slows or its direction of movement changes. (True or False)

True

### If you double the mass of an object while an unbalanced force remains constant?

the acceleration of the object is halved

### When you roll a ball across the floor, it comes to a stop because you are no longer exerting a force on it? (True or false)

false

### The tendency of a moving object to remain in unchanging motion in the absence of an unbalanced force is called?

inertia

### A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about?

10 N

### A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was?

30 m/s

### A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time?

300 M

### A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is?

1000 N

### A car accelerates at 2 meters/s/s. Assuming the car starts from rest, how far will it travel in 10 s?

100 m

### An object falls freely from rest on a planet where the acceleration due to gravity is twice as much as it is on Earth. In the first 5 seconds it falls a distance of?

250 m

### Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by?

both the same

### A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is?

10 times as much force as the force on the 1-kg book

### A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about?

the same

### A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?

6 N

### A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is?

zero

### A horse gallops a distance of 10 kilometers in a time of 30 minutes. Its average speed is?

20 km/hr

### A large and a small person wish to parachute at equal terminal velocities. The larger person will have to?

get a larger parachute

### A rock weighs 30 N on Earth. A second rock weighs 30 N on the moon. Which of the two rocks has the greater mass?

the one on the moon

### If less horizontal force is applied to a sliding object than is needed to maintain a constant velocity?

the object eventually slides to a stop

### You should "follow through" when hitting a ball because?

of the relationship between Δp = F Δt

### Suppose you slowly, and at constant speed, lift a book weighing 12 N from the floor to a shelf 2 m above the floor. Neglect air resistance. While you are lifting, the net force on the book is?

zero

### A 10-N block and a 1-N block lie on a horizontal frictionless table. To provide them with equal horizontal acceleration, we would have to push with?

10 times as much force on the heavier block

### A automobile and a baby carriage traveling at the same speed collide head-on. The impact force is?

the same for both

### A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the?

force the glove exerts on the ball

### An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is?

5 N

### The human body can, under certain conditions, withstand an acceleration of 10 g. What net force would produce this acceleration of a 50-kg person?

5000 N

### Two billiards balls, each of mass m, move towards each other at same speeds, v and collide head on. Their combined momentum after the collision is?

0

### A 2000 N car travels 50 m along a level road, powered by a drive force of 1000 N. The work done by the drive force is?

50,000 J

### In its monthly bill, the electric company charges you primarily for?

the electric energy you consume every month

### In order for you to get out of bed with the least amount of work, would it be better for your bed to be on the floor or a meter high?

It would be better for the bed to be a meter high, because then you would not need to do as much work in lifting yourself to your feet.

### Nearly all of the energy consumed today is provided by petroleum, coal, hydropower and nuclear sources. (true or false)

true

### he energy transformation that occurs during downhill skiing is?

grav E leads to kin E + therm E.

### Two students stand poised to leap off a high dive structure into the swimming pool below. Student B is twice as massive as student A. Which of the following is true?

student B did twice as much work climbing to the top of the structure

### Which of the following energy transformations represents the operation of a wind turbine [a device that uses the wind as an energy resource]?

Kin E leads to Electric E

### Difference between speed and velocity

relates to vectors and arrows.

same lengths=same speeds

different directions=different velocities

### Newton's first law of motion

If no external forces act on a moving object, then its

motion will continue on without changing.

### Newton's second law of motion

If a force F is applied to an object of mass m, the

object experiences a nonzero acceleration a in the

direction of the applied

### Why do things accelerate?

Objects will continue to move in the same direction and at a constant speed unless a force is applied

### Newton's third law of motion

For every applied force, there also occurs a force of equal magnitude acting in the opposite direction at precisely the same point.