which of the following statements is true? a. photons have energy, but no momentum. b. photons have momentum and energy, but no mass. c. photons have velocity and momentum, but no energy. d. photons have mass and velocity, but no momentum
1. ( ) in a rotating vertical cylinder (rotor-ride) a rider finds herself pressed with her back to the rotating wall. which is the correct free-body diagram for her?
a bowl of 331 g of water is placed in a microwave oven that puts out 590 watts (j/s). how long would it take in seconds to increase the temperature of the water from
when derrick looked up from his reading to see if the bus was coming, the lenses in his eyes changed shape in order to change from near to far focus. this is called:
the force parallel to a surface is 100n and the force perpendicular to the surface is 1000n. the coefficient of friction is 0.4. what is the frictional force (in n)?
is work performed when we apply more twist (torque) to change the radius of rotation of the bob? is the net acceleration still directed towards the axis of rotation?
a car accelerates from 12 m/sm/s to 22 m/sm/s in 6.2 ss . part a what was its acceleration assuming it is constant? express your answer using two significant figures.
the red giants and supergiants are only a tiny fraction of all known stars. why then do the giant stars account for most of the brightest stars we can see in the sky?
What is the period if the block’s mass is doubled? note that you do not know the value of either m or k , so do not assume any particular values for them. The required analysis involves thinking about ratios.
Both jupiter and saturn radiate more heat into space than they receive from the sun. What is the primary source of heat in the giant planets?.
A nonmechanical water meter could utilize the hall effect by applying a magnetic field across a metal pipe and measuring the hall voltage produced. What is the average fluid velocity in a 3. 50-cm-diameter pipe, if a 0. 750-t field across it creates a 75. 0-mv hall voltage?.
a see-saw consists of a pivot and a heavy (24 kg) uniform plank which is 3.0 m long. a 12kg box is placed at one end of the plank. how far from the other end should the pivot be so that the plank is balanced?
which of the following is a true statement about friction? a. friction only occurs when objects are in contact with each other. b. friction only occurs when objects are not in contact with each other. c. friction only occurs on earth. d. friction occurs when objects are in contact with each other or when objects are not in contact with each other.
