Question

Kinematics in 1-D

1. An object is moving with constant non-zero acceleration in the +x direction. The position versus time graph of this object is:

A) a horizontal straight line.

B) a vertical straight line.

C) a straight line making an angle with the time axis.

D) a parabolic curve.

2. A car traveling at 95 km/h strikes a tree. The front end of the car compresses and the driver comes to rest after traveling 0.80 m.

(a) What was the magnitude of the average acceleration of the driver during the collision?

(b) How long does it the car travel before coming to rest?

3. A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct?

A) Both its velocity and its acceleration point upward.

B) Its velocity points downward and its acceleration points upward.

C) Its velocity points upward and its acceleration points downward.

D) Both its velocity and its acceleration points downward.

4. A baseball is hit almost straight up into the air with a speed of 30 m/s. Estimate – (a) How high it goes?

(b) How long it is in the air?

Kinematics in 2-D: Vectors and Projectile motion

5. A projectile is launched with an initial velocity of vo m/s at an angle of θ° above the horizontal. Assume

the air resistance is negligible.

(a) Draw a diagram indicating its path – label the axes;

(b) Plot a graphs of horizontal and vertical components of the velocity as a function of time.

(c) Find the x and y components of the velocity vector at the initial position, at the highest point and just

before it hits the ground.

Newton’s Laws of Motion

6. A cable with a tension of 3450 N is horizontally pulling a 1200-kg car. If the coefficient of kinetic friction μk = 0.18, what is the acceleration of the car?

7. A block of mass M slides down a plane inclined at an angle θ, and the friction is negligible.

(a) What is the normal force?

(b) What is the net force parallel the plane?

(c) What is the acceleration of the block?

Circular Motion

8. A child whirls a ball in a vertical circle. Assuming the speed of the ball is constant (an approximation), when would the tension in the cord connected to the ball be greatest?

(a) At the top of the circle.

(b) At the bottom of the circle.

(c) Nowhere; the cord is stretched the same amount at all points.

9. The maximum speed with which a 1200-kg car can round a turn of radius 90.0 m on a flat road is 24 m/s. What is the coefficient of friction between tires and road? Is this coefficient of static friction or kinetic friction?

Work and Energy

10. A person pulls a 50-kg crate over a displacement of 40-m along a horizontal floor with a rope of 100N tension. The rope makes an angle of 37o with the horizontal surface. The floor is rough, exerting a friction force of 60 N.

(a) Determine the work done by each of the forces acting on the crate.

(b) Determine the final speed of the crate assuming it started from rest.

11. Starting from test, a 16.0-kg child descends a frictionless slide 2.20 m high and reaches the bottom of the slide. What is her speed at the bottom of the slide?

Linear Momentum

12. A large semitrailer truck and a small car have equal momentum. How do their speeds compare?

A) The truck has a much higher speed than the car.

B) Both have the same speed.

C) The truck has a much lower speed than the car.

If they collide, after collision, how do their change in momentum compare?

A) The truck has a much higher change in momentum.

B) Both have the same change in momentum.

C) The truck has a much lower change in momentum.

13. A 7700-kg boxcar traveling 14 m/s strikes a second car at rest. The two stick together and move off with a speed of 5.0 m/s. What is the mass of the second car?

Rotational Motion

14. How fast (in rpm) must a centrifuge rotate if a particle 8.0 cm from the axis of rotation is to experience

an acceleration of 100,000 g’s?

15. Two spheres have the same radius (R) and same mass (M). One sphere is solid, and the other is hollow and made of a denser material. They start from rest at the top of an incline (rolls without slipping).

(a) Which has greater moment of inertia?

(b) Which has the greater rotational kinetic energy?

(c) Which has the greater total kinetic energy at the bottom?

(d) Which has the greater speed at the bottom?

(e) Given Isolid shpere =(2/5) MR2. What is its total kinetic energy?

16. A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

A) her moment of inertia decreases and her angular speed increases.

B) her moment of inertia decreases and her angular speed decreases.

C) her moment of inertia increases and her angular speed increases.

D) her moment of inertia increases and her angular speed decreases.

E) her moment of inertia increases and her angular speed remains the same

Elasticity

17. You have two ropes with different Young’s modulus, but the same area of cross section and length. You apply the same force on both of these. The change in the length is -

A) More for the rope with higher Young’s modulus

B) Less for the rope with higher Young’s modulus

C) Same for both the ropes.

Gravitation

18. Two small objects, with masses M1 and M2 are originally a distance R apart, and the gravitational force on each one has magnitude F. The second object has its mass changed to 2M2 and the distance is changed to R/2. What is the magnitude of the new gravitational force?

A) F/4 B) F/8 C) 4F D) 8F E) 16F

19. Two satellites orbit the Earth in circular orbits of the same radius. One satellite is twice as massive as the other. Which statement is true about the speeds of these satellites?

A) The heavier satellite moves twice as fast as the lighter one.

B) The two satellites have the same speed.

C) The lighter satellite moves twice as fast as the heavier one.

D) The ratio of their speeds depends on the orbital radius.

Oscillations and Waves

20. A fisherman’s scale stretches 3.3 cm when a 2.6-kg fish hangs from it. The fish is pulled down 2.5 cm more and released so that it oscillates up and down?

(a) What is the spring stiffness constant?

(b) What will be the amplitude?

(c) What is the period and frequency of oscillation?

21. A mass on a string of unknown length oscillates as a pendulum with a period T. What is the period if -

A) The mass is doubled?

B) The string length is doubled?

C) The string length is halved?

D) The amplitude is doubled?

22. A 2.1-m long string is tied at both ends and it vibrates with a fundamental frequency of 44 Hz.

(a) What is the speed of the waves on the string?

(b) What are the 2nd and 3rd harmonics?

(c) Sketch the standing wave pattern for the fundamental, 2nd and 3rd harmonics.

For each case, indicate the nodes, antinodes, wavelength of the wave.

Fluids

23. As shown in the figure, fluid fills a container having several

sections. At which of the indicated points is the pressure greatest?

(a) A

(b) B

(c) C

(d) D

(e) The pressure is the same at each of the labeled points.

24. Fluid flows at 2.0 m/s through a pipe of diameter 3.0 cm. What is the volume flow rate of the fluid?

25. When a baseball curves to the left (a curveball), air is flowing

(a) faster over the left side than over the right side.

(b) faster over the right side than over the left side.

(c) faster over the top than underneath.

(d) at the same speed all around the baseball, but the ball curves as a result of the way the wind is blowing on the field.

Heat and Thermodynamics –

26. A grandfather clock uses a brass pendulum to keep perfect time at room temperature. On a very hot summer day, how will the grandfather clock be affected?

(a) clock will run slower than usual (b) clock will still keep perfect time (c) clock will run faster than usual

27. By what primary heat transfer mechanism does the sun warm the earth?

A) convection

B) conduction

C) radiation

D) All of the above processes are equally important in combination.

Answer 1