Phyc Exam

If only 1 force is acting on an object, can it be in equilibrium? (Yes or no)

1) no

1) A heavy truck has more momentum than a passenger car moving at the same speed because the truck; a) has greater mass b) has greater speed c) is not streamlined d) has a large wheelbase

A

An object in equilibrium must not have a) acceleration. b) any forces acting on it. c) any torques acting on it d) all of the above. e) none of the above.

A

Kinetic energy is. . .? a. Energy in motion b. Stored energy c. Energy we never use d. Lack of energy

A

The moment of inertia I is the rotational analogue of a) mass, from linear motion. b) force, from linear motion. c) kinetic energy, from linear motion. d) orbital period, from circular motion. e) none of the above

A

What happens to the kinetic energy of a moving object if the net work done is positive? a. The kinetic energy increases b. The kinetic energy decreases c. The kinetic energy remains the same d. The kinetic energy is zero e. The kinetic energy becomes negative

A

1) A heavy object and a light object have the same momentum. Which has the greater speed? a) heavy object b) light object c) both have the same speed d) the heavy object has a zero speed while the light object has a nonzero speed

B

1) A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change? a) the clay b) the ball c) Both of them experience the same non-zero momentum change. d) Both of them experience zero momentum change.

B

1) For a point on the rim of a flywheel that rotates at constant angular velocity a) The tangential acceleration and the centripetal acceleration are zero .b) The tangential acceleration is zero and the centripetal acceleration is constant. c) The centripetal acceleration is zero and the tangential acceleration is constant. d) The tangential acceleration is zero and the centripetal acceleration is constant in magnitude but changing in direction. e) The tangential and centripetal acceleration are both changing in both magnitude and direction.

B

A machine does 2500 J of work in 1 min. What is the power developed by the machine? a. 21 W b. 42 W c. 150 W d. 2500 W e. 150000 W

B

The S.I unit for pressure is. . .? a. Newton b. Pascal c. Ft.lb d. kg/m

B

What is energy? a. Power b. The capacity to do work c. Electricity d. Water

B

1) The unit of energy in the metric system (SI) is a. Newton b. ft.lb c. Joule d. Watt

C

A container with a mass of 5 kg is lifted to a height of 8 m. How much work is done by the gravitational force? a). 400 J b). -400 J c). zero d). 50 J e). -50J

C

An object is thrown straight up. Which of the following is true about the sign of work done by the gravitational force while the object moves up and then down? a. Work is positive on the way up, work is positive on the way down b. Work is negative on the way up, work is negative on the way down c. Work is negative on the way up, work is positive on the way down d. Work is positive on the way up, work is negative on the way down e. Work is zero the way up, work is zero on the way down

C

1) A change in momentum may result from a) an acceleration b) a force c) an impulse d) all of the above

D

1) Momentum is conserved when? a) in an elastic collision of two balls b) in an inelastic collision of two balls c) in the absence of an external force d) in all of the preceding cases

D

A 4 kg ball is attached to a 1.5 m long string and whirled in a horizontal circle at a constant speed 5 m/s. How much work is done on the ball during one period? a. 9 J b. 4.5 J c. 2 J d. 0 J

D

Torque is the rotational analogue of: a) kinetic energy b) linear momentum c) acceleration d) force e) mass

D

Air pressure increases with height. True or False?

False

A car travelling at a constant speed has a net force of zero acting on it. True or False?

True

A roller coaster uses both kinetic and potential energy. True or False?

True

Which of the following rotational quantities are the same for all points on a solid rotating disk? a) Angular velocity. b) Tangential velocity. c) Tangential acceleration . d) Centripetal acceleration . e) all of the above.

a & d are true

1) A ball is thrown upwards by a passenger on a train moving at a constant velocity. Ignoring air resistance, which of the following will be true? a. The ball will land back in the passenger's hand. b. The ball will land behind the passenger. c. The ball will land in front of the passenger. None of the above.

a) The ball will land back in the passenger's hand

1) A passenger on a train moving at a constant velocity v1, throws a ball forwards to another passenger with a velocity v2. Ignoring air resistance, which of the following will be true? a. The velocity of the ball will be v1 - v2. b. The velocity of the ball will be v1 + v2. c. The velocity of the ball will be v1 * v2. d. The velocity of the ball will be v1 / v2. None of the above.

a. b) The velocity of the ball will be v1 + v2.

A satellite of mass m moves with a constant speed v in a circular orbit of radius r. Which of the following statements are true? a) Its angular speed is v/r. b) Its tangential acceleration is zero. c) The magnitude of its centripetal acceleration is constant.

all are true

1) Which of the following particles have an acceleration? a. A particle moving in a straight line at a constant speed. b. A particle moving around a curve at a constant speed. c. Both of the above. None of the above.

b) A particle moving around a curve at a constant speed

1) A ball is thrown straight up in the air. For which situation is both the velocity and the acceleration zero? a. On the way up. b. At the top of the flight path. c. On the way down. d. halfway up and halfway down. None of the above.

b) At the top of the flight path

1) You see 3 carts moving to the left. Which cart experiences a net acceleration to the left? a. Cart A which is moving at a constant speed. b. Cart B which is speeding up. c. Cart C which is slowing down. None of the above.

b) Cart B which is speeding up

1) A person is twirling a ball on a string when the string breaks and the ball flies off at a tangent to the circular path. Which of the following best describes why this happens? a. Newton's zeroth law of motion. b. Newton's first law of motion. c. Newton's second law of motion. d. Newton's third law of motion. e. None of Newton's laws of motion adequately explains the ball's motion when the string breaks.

b) Newton's first law of motion.

The density of lead is greater than iron, and both are denser than water. The buoyant force on a lead object compared to that on an iron object of the same size is... a. Greater than b. Less than c. The same

c. The same

If the velocity of an object is not zero, the acceleration must be zero. True or false?

false