Final Exam 1-8

(Plug and Play) Ball bearings are made by letting drops of molted metal fall, and the drops solidify as they fall. They require 5.0 s to solidify. From what minimum height must they be dropped?

• 122.5 m

• 40 m

• 100 m

• 12 m

(plug and play) A cannon tilted upward 30° fires a cannonball with a speed of 100 m/s. What is the component of the cannonball’s velocity parallel to the ground?

• about 50 m/s

• about 100 m/s

• about 87 m/s

• about 10m/s

Plug and play. A construction worker with a weight of 850 N stands on a roof that is sloped at 20°. What is the magnitude of the normal force of the roof on the worker?

• 810 N

• 900 N

• 850 N

• 799 N

(Plug and Play) A woman has a mass of 55 kg, what is her weight on earth and what is her weight on Mars where g = 3.76 m/s2 ?

• 540 N and 210 N

• 100 N and 600 N

• 600 N and 200 N

• 300 N and 700 N

(plug and play) A 1500 kg car takes a 50-m-radius unbanked curve at 15 m/s. What is the size of the friction force on the car?

• 1200 N

• 6750 N

• 8000 N

• 300 N

(plug and play) A skater moving to the left (negative direction) across frictionless ice at 7.2 m/s hits a 3.0-m-wide patch of rough ice. She slows steadily, then continues on at 6.0 m/s. What is her acceleration on the rough ice? Consider both magnitude and direction

• -1m/s^2

• +2.64 m/s^2

• -3m/s^2

• +7 m/s^2

(Graphics) A particle starts from x₀ = 10 m at t₀ = 0 s and moves with the velocity graph show below. (Exercise 2.6)

Does this particle have a turning point? If so, at what time

• No, it doesn't turn

• Yes, at 0 sec

• Yes, at 1 sec

• Yes, at 4 sec

(graphics) Four forces are exerted on the object shown below. (Forces are measured in newtons, abbreviated N.) The net force on the object is N. What are (a) and (b) ? Give your answers in component form.

• -1.6 i , 2.9 j

• 1 i, 5 j

• 3 i, 4 j

• -4.5 i, 3.0 j

(graphic) A physics student on Planet Exidor throws a ball, and it follows the parabolic trajectory shown below. The ball’s position is shown at 1 s intervals until t = 3 s. At t = 1 s, the ball’s velocity is m/s. What is gravity?

• 4 m/s^2

• 2 m/s^2

• 9.8 m/s^2

• 6 m/s^2

(Graphic)The fig. below shows the angular velocity graph of the crankshaft in a car. What is the crankshaft’s angular acceleration at 1s, 3 s, and 5 s?

• 1, 3, 5 rad/s^2

• 100, 0, -50 rad/s^2

• 50, 10, 100 rad/s^2

• no enough information