BackA bicylist of mass 75 kg (including the bicycle) can coast down a 5.0° hill at a steady speed of 12 km/h. Pumping hard, the cyclist can descend the hill at a speed of 32 km/h. Using the same power, at what speed can the cyclist climb the same hill? Assume the force of friction is proportional to the square of the speed v; that is, Ffr = bv2, where b is a constant.
If the heating element of an electric dryer is rated at when connected to a line, what is the current drawn by the dryer?
An electric device uses watts of power. If the voltage across the device is volts, what is the current flowing through the device?
Which of the following statements about is true?
A light bulb operates for . How many of energy does it consume during that time?
If a monochromatic light source has a power output of (where ), and each photon has energy , how many photons are emitted per second?
If two identical light bulbs, A and B, are connected in series to a battery and a switch is connected in parallel with bulb
Which of the following expressions correctly represents the average power delivered by a force acting on an object over a time interval with work done ?
Which physical quantity is measured in watts ()?
An electric furnace is rated at and operates on . What is the rate at which it produces heat output?
A current of flows through a resistor of resistance . How much power is dissipated by the resistor?
How many watts of power are required to exert a force of over a distance of in ?
For a hydroelectric turbine, what is the maximum possible power output if water of density flows at a rate from a height above the turbine, assuming 100% efficiency and neglecting losses?
Which of the following is the best estimate for the power usage (in ) of a typical electric oven?
Which of the following is the best estimate for the power () in watts () of a typical household bread toaster?