Two gliders collide on an air track. glider 1 has a mass of 7.0 kg, and glider 2 has a mass of 4.0 kg. before the collision, glider 1 had a velocity of 2.0 m/s, and glider 2 had a velocity of -5.0 m/s. if the collision is perfectly elastic, what is the total kinetic energy of both gliders after the collision?

a.-36.0 j
b. 36.0 j
c. 64.0 j
d. 128.0 j

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.

On mars a rock falls an unknown vertical distance from a resting position and lands in a crater. if it takes the rock 2.5 seconds to fall, how high is the cliff the rock fell from? mars' surface gravity is 3.8 m/s2. a. 9.5 m b. 11.9 m c. 15.2 m d. 23.8 m