A 60kg woman does a step-up/step-down task using a 25cm platform. A full step cycle consists of a step-up a followed by a step-down. During each step-up assume she is lifting her entire mass with one leg. Ignoring accelerations and motion in the horizontal direction a. How many step-ups would the woman need to do to expend at least 1kCal of energy? b. How quickly (steps/min) would she need to do the activity if the goal was expend at least .05kCal/s? (assume step up and down time is the same)

Consider a block of mass 25 kg being pulled up a rough incline by a 250-N pulling force parallel to the incline. The incline makes an angle of 24 degrees with the horizontal. The coefficient of kinetic friction is 0.34, the block has an initial speed of 1.28 m/s and was pulled a total distance of 3.15 m. a. How much work is done by gravity? b. How much energy is lost due to friction? c. How much work is done by the pulling force? d. Compute for the net work done on the block. e. What is the speed of the crate after being pulled 3.15 m?

The maximum energy a bone can absorb without breaking is surprisingly small. For a healthy human of mass 60 kg, experimental data show that the leg bones of both legs can absorb about 200 J.a. From what maximum height could a person jump and land rigidly upright on both feet without breaking his legs? Assume that all the energy is absorbed in the leg bones in a rigid landing.b. People jump from much greater heights than this; explain how this is possible.Hint: Think about how people land when they jump from greater heights.

BACK NE Chapter 10, Problem 058 Your answer is partially correct. Try again. If R = 22.2 cm, M = 552 g, and m = 191 g in the figure, find the speed of the block after it has descended 43.4 cm starting from rest. Solve the problem using energy conservation principles. (c) (a) (b) NumberT Unitšm/s

Starting from rest, a ball of mass 3 kg experiences a constant force of 12 N. What is the final kinetic energy (in J) of the ball after it has traveled a distance of 2 m? A. 6J B. 24) O C. 4J D.72) E. 36J

QUESTION 11 Starting from rest, a ball of mass 3 kg experiences a constant force of 9 N. What is the final kinetic energy (in J) of the ball after it has traveled a distance of 8 m? A. 216J B, 72J C.3J D. 24J E, 27J

Q9.

A 225g cart compresses a horizontal 650J/m² spring 3.2cm and is released from rest. The cart travels horizontally before going down a ramp. The top of the ramp is 25cm higher than the bottom. A. What is the speed of the cart after the spring decompresses but before it goes down the ramp? B. What is the speed of the cart at the bottom of the ramp?

8

1400 kg Polo STi accelerates from rest to 20 m/s in exactly 2 seconds. a. Calculate the change in kinetic energy of the car (in kJ). b. Calculate the power of the car's engine (in kW)