an object of mass m is at rest at the top of a smooth slope of height h and length l. the coefficient of kinetic friction between the object and the surface, ? k, is small enough that the object will slide down the slope if given a very small push to get it started.
1. find an expression for the object's speed at the bottom of the slope.
2. sam, whose mass is 70kg , stands at the top of a 10-m-high, 80-m-long snow-covered slope. his skis have a coefficient of kinetic friction on snow of 0.07. if he uses his poles to get started, then glides down, what is his speed at the bottom?

The slope of a velocity time graph over any interval of time gives the during that interval

Which of these metals are magnetic?

Simon is writing a story about an astronaut whose spacecraft has been boarded by space pirates. the astronaut has her lucky penny in her hand behind her back as the space pirates break into the control room. she has just locked the controls so that the ship is accelerating in the direction of the control room’s ceiling. simon wants the astronaut to use the penny to hit a button on the control panel to turn off the lights and escape. the button is located a short distance behind and below the astronaut’s hands. how should simon use the theory of relativity to describe what the astronaut must do in order to hit the button?