Aroller coaster car is elevated to a height of 30 m and released from rest to roll along a track. at a certain time t it is at a height of 2 m and has lost 25.000 j of energy to friction. the car has a mass of 800 kg. answer the following questions. (a) how fast is the car going at time t? (b) how fast would the car be going at time t if the track were frictionless?

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.