If a rock is thrown vertically upward from the surface of mars with velocity 15 mys, its height after t seconds is h − 15t 2 1.86t2. (a) what is the velocity of the rock after 2 s? (b) what is the velocity of the rock when its height is 25 m on its way up? on its way down?

Which statement best explains why an object weight less on mercury than it does on earth

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0

While carrying a heavy box up the stairs,you set the box on a step and rest. then you pick up the box and carry it to the top of the stairs. describe these actions in terms of balanced and unbalanced forces acting on the box.