Question 1:

On September 8, 2004, the Genesis spacecraft crashed in the Utah desert because its parachute did not open. The 210-kg capsule hit the ground at 311 km/h and penetrated the soil to a depth of 81.0 cm.

Part - What force did the ground exert on the capsule during the crash? Express the force as a multiple of the capsule's weight.

Question 2:

You are lowering two boxes, one on top of the other, down the ramp shown in the figure by pulling on a rope parallel to the surface of the ramp. Both boxes move together at a constant speed of 12.0cm/s . The coefficient of kinetic friction between the ramp and the lower box is 0.500, and the coefficient of static friction between the two boxes is 0.783.

Part A
What force do you need to exert to accomplish this?

Question 3:

A bowling ball weighing 70.6N is attached to the ceiling by a rope of length 3.81m . The ball is pulled to one side and released; it then swings back and forth as a pendulum. As the rope swings through the vertical, the speed of the bowling ball is 4.30m/s .

Part A
What is the acceleration of the bowling ball, in magnitude and direction, at this instant?

Part B

What is the tension in the rope at this instant?

Problem

Block A in the figure weighs 68.2N . The coefficient of static friction between the block and the surface on which it rests is 0.29. The weight w is 10.1N and the system is in equilibrium.

Question 4:

A 75.0-kg painter climbs a ladder that is 2.71mlong leaning against a vertical wall. The ladder makes an 26.0° angle with the wall.

Part A

How much work does gravity do on the painter?

Part B

Does the answer to part A depend on whether the painter climbs at constant speed or accelerates up the ladder?

Question 5:

A loaded grocery cart is rolling across a parking lot in a strong wind. You apply a constant force F? =( 29N )i^-( 35N )j^ to the cart as it undergoes a displacement s? =(- 8.8m )i^-(3.7m )j^.

Part A

How much work does the force you apply do on the grocery cart?

Question 6:

A 1.50kg book is sliding along a rough horizontal surface. At point A it is moving at 3.21m/s , and at point B it has slowed to 1.25m/s .

Part A

How much work was done on the book between A and B?

Part B

If -0.750J of work is done on the book from B to C, how fast is it moving at point C?

Part C

How fast would it be moving at C if 0.750J of work were done on it from B to C?

Question 7:

You throw a 20-N rock vertically into the air from ground level. You observe that when it is a height 16.0m above the ground, it is traveling at a speed of 25.9m/s upward.

Part A

Use the work-energy theorem to find its speed just as it left the ground.

Part B

Use the work-energy theorem to find its maximum height.

Question 8:

A 20.0-kg rock is sliding on a rough, horizontal surface at 8.00 m/s and eventually stops due to friction. The coefficient of kinetic friction between the rock and the surface is 0.200.

Part A
What average thermal power is produced as the rock stops?

Question 9:

A 5.0-kg box moving at 4.0m/s on a horizontal, frictionless surface runs into a light spring of force constant 50N/cm .

Part A

Use the work-energy theorem to find the maximum compression of the spring.

Express your answer using two significant figures.
x = cm

Problem - A block of ice with mass 6.30kg is initially at rest on a frictionless, horizontal surface. A worker then applies a horizontal force F? to it. As a result, the block moves along the x-axis such that its position as a function of time is given by x(t)=αt₂+βt₃, where α = 0.200m/s² and β= 2.09×10^-2 m/s³ .

Part A

Calculate the velocity of the object at time t = 3.60s .

Express your answer to three significant figures.

v = m/s

Part B

Calculate the magnitude of F?  at time t = 3.60s .

Express your answer to three significant figures.

F = N

Part C

Calculate the work done by the force F?  during the first time interval of 3.60s of the motion.

Express your answer to three significant figures.