a track increases velocity from 30 m per second to 60 m per second in 10 seconds:a)calculate the acceleration of the track b) the displacement in 4 second

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

Apropagating wave in space with electric and magnetic components. these components oscillate at right angles to each other. it may travel in a vacuum.

What is the change in internal energy if 20 j of heat is released from a system and the system does 50 j of work on the surroundings? a. -70 j b. 30 j c. -30 j d. 70 j