Physics Final 1

Question 1

Using the standard physical meanings of the quantities t, x, v, and a, choose which of the following equations are dimensionally consistent.

Answer 1

Consistent V^2 = 2ax
Not Consistent v=at^2/2
Not Consistent t=a/v
Not consistent x= v/2a

Question 2

Is it possible for a car to circle a race track at constant velocity?

Answer 2

No

Question 3

Can the car circle the track at constant speed?

Answer 3

Yes

Question 4

An object that is accelerating must have a nonzero average velocity.

Answer 4

False

Question 5

An object with a nonzero velocity can have an acceleration of zero.

Answer 5

True

Question 6

An object with a nonzero acceleration at some instant of time can have a velocity of zero at that instant.

Answer 6

True

Question 7

A ball is dropped from rest. After T seconds, the ball has fallen a distance d. Relative to this location, how much farther does it fall after another 4T seconds?

Answer 7

24D

Question 8

The magnitude of the sum of two vectors is always greater than the magnitude of either vector.

Answer 8

False

Question 9

It is possible for a component of a vector to be zero if the vector itself is not zero.

Answer 9

True

Question 10

It is possible for a vector to be zero, while a component of the vector is not zero.

Answer 10

False

Question 11

An object can be in motion and still have zero net force acting on it.

Answer 11

True

Question 12

In order to move a massive crate sitting on the floor, the force you apply to the crate has to overcome the force of the crate pushing back on you.

Answer 12

False

Question 13

An object can be moving in one direction while the net force acting on it is in another direction.

Answer 13

True

Question 14

An object at rest has no forces acting on it.

Answer 14

False

Question 15

A bird cage, with a parrot inside, hangs from a scale. The parrot decides to hop from one perch to another (without flapping its wings). The total weight of the parrot and cage is 50 N. For the following questions, assume that the scale responds rapidly enough that it gives an accurate reading at every instant.
What is the reading on the scale before the parrot jumps?

Answer 15

50 N

Question 16

A bird cage, with a parrot inside, hangs from a scale. The parrot decides to hop from one perch to another (without flapping its wings). The total weight of the parrot and cage is 50 N. For the following questions, assume that the scale responds rapidly enough that it gives an accurate reading at every instant.
What is the reading on the scale as the parrot starts its jump?

Answer 16

More than 50 N.

Question 17

A bird cage, with a parrot inside, hangs from a scale. The parrot decides to hop from one perch to another (without flapping its wings). The total weight of the parrot and cage is 50 N. For the following questions, assume that the scale responds rapidly enough that it gives an accurate reading at every instant.
What is the reading on the scale when the parrot is in the air?

Answer 17

Less than 50 N.

Question 18

A bird cage, with a parrot inside, hangs from a scale. The parrot decides to hop from one perch to another (without flapping its wings). The total weight of the parrot and cage is 50 N. For the following questions, assume that the scale responds rapidly enough that it gives an accurate reading at every instant.
What is the reading on the scale as the parrot lands on the other perch?

Answer 18

More than 50 N.

Question 19

Stones are thrown horizontally, with the same initial velocity, from the tops of two different buildings, A and B. The stone from building A lands 4 times as far from the base of the building as does the stone from building B. What is the ratio of building A’s height to building B’s height?

Answer 19

16

Question 20

The potential energy of a system can be negative.

Answer 20

True

Question 21

If the force on an object is zero, the potential energy of the system is zero.

Answer 21

False

Question 22

If the potential energy of the system is zero, the force on the object is zero.

Answer 22

False

Question 23

You drop a ball to the ground from rest, and, from the same height, throw a second identical ball down to the ground. Their change in gravitational potential energies are different.

Answer 23

False

Question 24

When air resistance is taken into account, a ball thrown directly upward spends more time on the way down than on the way up.

Answer 24

True

Question 25

A slow-moving elephant can have more kinetic energy than a fast-moving cheetah.

Answer 25

True

Question 26

Friction can do positive work on an object.

Answer 26

True

Question 27

Static friction does no work on an object.

Answer 27

False

Question 28

Motor A does twice the work as motor B. Therefore, motor A produces twice as much power as motor B.

Answer 28

False

Question 29

A massive elephant can have less kinetic energy than a lightweight gazelle.

Answer 29

True

Question 30

Only the net force acting on an object can do work.

Answer 30

False