Conceptual questions test 1

Question 1

Who discovered the 3 laws of mechanics and the law of gravity?

(a) Kepler
(b) Newton
(c) Ptolemy
(d) Copernicus
(e) Galileo

Answer 1

B.

Newton

Question 2

8. You throw a football to a friend, what is the velocity of the football when it reaches its
   maximum height?
   (a) 0 m/s
   (b) 10 m/s downward
   (c) 10 m/s upward
   (d) The same as its horizontal velocity at that time
   (e) 10 m/s horizontally

Answer 2

d,

The same as its horizontal velocity at that time

Question 3

11. A 2 kg ball and a 20 kg ball are held at a height h=2 m above the ground. Which one
    has the greater gravitational potential energy (GPE)?
    (a) The 2 kg ball
    (b) The 20 kg ball
    (c) They both have the same GPE

Answer 3

B.

the 20 kg ball since it can overcome more air resistance and would have a harder impact due to weight

Question 4

12. Two kids are sitting at the center of a merry-go-round as it spins horizontally. What
    happens to the speed of the merry-go-round if one child moves to the outer edge?
    (a) It speeds up
    (b) It slows down
    (c) Conservation of angular momentum means that it spins at the same rate

Answer 4

b

It slows down

Question 5

13. Two kids are sitting at the center of a merry-go-round as it spins horizontally. What
    happens to the rotational inertia of the merry-go-round if one child moves to the outer
    edge?
    (d) It gets larger
    (e) It gets smaller
    (f) It stays the same

Answer 5

It gets larger

Question 6

16. Who is considered the father of modern science?
    (a) Kepler
    (b) Newton
    (c) Ptolemy
    (d) Copernicus
    (e) Galileo

Answer 6

e.

Galileo

Question 7

23. Which force is usually stronger?
    (a) Static friction
    (b) Kinetic friction
    (c) They are always the same

Answer 7

a.

Static friction

Question 8

24. You drop two water balloons from your dorm; one from the 2nd floor and one from
    the 5th floor. Which water balloon has the greater acceleration?
    (a) The one dropped from the 2nd floor
    (b) The one dropped from the 5th floor
    (c) They both have the same acceleration

Answer 8

c.

They both have the same acceleration

Question 9

25. You drop two water balloons from your dorm; one from the 2nd floor and one from
    the 5th floor. Which water balloon has the greater kinetic energy right before the ground?
    (a) The one dropped from the 2nd floor
    (b) The one dropped from the 5th floor
    (c) They both have the same acceleration

Answer 9

b.

The one dropped from the 5th floor.

Question 10

Who is known as the “Father of modern physics”?

Answer 10

Galileo

Question 11

Who made the first detailed measurements of the motion of a planet?

Answer 11

Brahe

Question 12

Who discovered the 3 laws of mechanics and the law of gravity?

Answer 12

Newton

Question 13

Who discovered the laws of planetary motion?

Answer 13

Kepler

Question 14

These are all examples of _______:
Shaking your hands after washing to remove water; stomping your feet on the ground to
remove snow from your shoes; pulling the cloth out from under the dishes.

Answer 14

Inertia

Question 15

What quantity is a measure of somethings inertia?

Answer 15

Mass

Question 16

Does a falling object fall the same distance during each second that it if falling?

Answer 16

Not until terminal speed

Question 17

What is the acceleration of a projectile while it is rising and falling?

Answer 17

10m/s downward

Question 18

Projectile

Answer 18

A projectile is an object that is given an initial velocity and then moves under the influence of gravity alone

Question 19

To hit the center of a target, where should a rifle be aimed?

Answer 19

Above the middle to account for gravity

Question 20

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.

Answer 20

Newtons second law

Question 21

Acceleration units

Answer 21

m/s^2

Question 22

3 non contact forces

Answer 22

Magnetism, Gravity, Electric force

Question 23

A box of weight W rests on the floor. Identify the action/reaction forces acting on the box.

Answer 23

The box exerts a downward force on the floor equal to its weight, and the floor exerts an equal upward force on the box. Thus the weight of the box and the upward force of the floor on the box form an action/reaction pair.

Question 24

Does the kinetic energy of an object depend on which direction it is moving?

Answer 24

No, KE is a scalar quantity

Question 25

Elastic collision

Answer 25

In an elastic collision, the total kinetic energy of the objects before and after the collision is the same.

Question 26

Inelastic collision

Answer 26

In an inelastic collision the kinetic energy is not the same, it is usually less after the collision

Question 27

Totally inelastic collision

Answer 27

In a totally inelastic collision, the objects stick together after they collide. In a totally inelastic collision, the loss of kinetic energy is as large as possible

Question 28

In a class demonstration a tennis ball on top of a basketball are dropped. When the basketball hits the ground, the tennis ball strongly rebounds upward. Why?  

Answer 28

The tennis ball gets a big “kick” because its mass is much less than the mass of the basketball.

Question 29

What is the definition of WORK? In what units is it measured?

Answer 29

In physics work is done when a force is applied to an object to move it through a certain distance. The work is the force x the distance.  Units Work in Joules (J),  Force in Newtons, and distance in meters. One Joule (J) is one N x 1 m

Question 30

You lift a heavy weight over your head and hold it there. When are you doing work?

Answer 30

When you lift it up and movement occurs.(F*Distance)

Question 31

You carry a 200 N weight over a distance of 7 m. How much work do you do?

Answer 31

No work, because the force and motion are in different directions

Question 32

What is the physics definition of a machine?

Answer 32

A machine is any device that allows us to accomplish a task more easily. Reduces work.

Question 33

If you throw a ball upwards what is the Potential energy at the top right before it starts falling

Answer 33

PE=m*g*h

Question 34

Is energy stored in a compressed or stretched spring?

Answer 34

Both, work must be done to get them to this state and once released the PE turns to KE.

Question 35

A child swings a ball attached to a string in a circle at a constant speed. Is the ball accelerating and if so what force provides this acceleration?

Answer 35

The ball is accelerating and the force that provides the acceleration is the tension in the string.

Question 36

ac is

Answer 36

centripetal force

Question 37

What maximum torque could be applied with a force of 50 N using a crowbar that is 1 m long?

Answer 37

1m*50N= 50 N

Question 38

If the net force on an object is zero, do this imply that the net torque must also be zero?

Answer 38

No, you could have opposing forces with different levels of force and different levels of torque

Question 39

What factors determine the rotational inertia of an object?

Answer 39

The rotational inertia of an object depends on its mass and how the mass is distributed relative to the axis of rotation.

Question 40

What is the law of conservation of rotational momentum?

Answer 40

In the absence of any external torques, the total rotational momentum of a rigid body is a constant (conserved).  

Question 41

Two metal spheres, one that is hollow and one that is solid are constructed of different materials but have the same mass and diameter. If the spheres roll down an inclined plane from the same initial height, which one will reach the bottom of the incline first?

Answer 41

The Solid one, because its smaller rotational inertia.

Question 42

Why does a spinning ice skater spin faster when she pulls her arms in close to her body?

Answer 42

When a spinning skater pulls her arms in close to her body, she lowers her rotational inertia.

Question 43

Why is a bicycle stable when it is moving but tends to tip over when it stops?

Answer 43

A spinning bike wheel has rotational momentum which is conserved both in magnitude and direction. So while the bike is moving and the wheels are rotating, the tendency to preserve the rotational momentum keeps the bike from tipping over. When the bike is not moving, it has no rotational momentum.