A horizontal spring with spring constant 85 N/m N/m extends outward from a wall just above floor level. A 8.5 kg kg box sliding across a frictionless floor hits the end of the spring and compresses it 6.5 cm cm before the spring expands and shoots the box back out. How fast was the box going when it hit the spring?

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct

Ablock having mass m slides down an inclined plane. the force of friction between the block and the inclined plane is f, the block's weight is m g, and the normal force is n. (a) draw a free – body force diagram showing the forces acting on the block. (b) write down all relevant newton’s equations for a given situation.

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.