A champion athlete can produce one horsepower (746 W) for a short period of time. If a 70-kg athlete were to bicycle from the bottom to the top of a 254-m high mountain while expending power at the rate of 532 Watts, she would take at least how many seconds to reach the top.

You are driving to work at 60 mph and need to accelerate to 75 mph. How long will it take to reach this speed? Express this quantity in units of seconds. Assume the engine is rated at 140 hp and is 25% efficient. The combined vehicle and driver mass is 2970 lbm.

What average mechanical power (in W) must a 60.0 kg mountain climber generate to climb to the summit of a hill of height 365 m in 49.0 min? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body. HINT

A motorcyclist drives up a 3.1-meter tall ramp and leaves the ramp with a speed of 42.5 m/s.  If his speed is 37.8 m/s when he reaches the peak of his path, what is the maximum height (in m) above ground that he reaches? (Use energy, not kinematic equations.)

A 699-kg elevator starts from rest and moves upward for 2.60 s with constant acceleration until it reaches its cruising speed, 1.83 m/s. (a) What is the average power of the elevator motor during this period? hp (b) How does this amount of power compare with its power during an upward trip with constant speed? (Give the power during an upward trip with constant speed.) hp Need Help? Read It

Suppose a 975-kg car can produce a useful power output of 45.5 hp (1 hp = 746 W).  (a) How long, in seconds, will it take the car to reach a speed of 15.5 m/s, neglecting friction.   (b)  How long, in seconds, will this acceleration take if the car also climbs a 2.9-m high hill in the process?

A 55 kg sprinter, starting from rest, runs 55 m in 7.0 s at constant acceleration.What is the sprinter's power output at 2.0 s, 4.0 s, and 6.0 s?

What average mechanical power (in W) must a 61.5 kg mountain climber generate to climb to the summit of a hill of height 405 m in 46.0 min? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body.

A 2,200-lb sports car with a power of 135 hp can accelerate from zero to 110 mph. How longapproximately will it take to accomplish this?

An advertisement claims that a(n) 1600 kg car can accelerate from rest to 26 m/s in 8.4 s. Given: Unit conversion: 746 W/hp. What average power must the motor pro- duce to cause this acceleration, if we ignore friction and air resistance? Answer in units of hp. Answer in units of hp. Your response... PALETTE