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in the 74 s after lift-off, the shuttle challenger travels 36 km. assume constant acceleration, calculate a) the acceleration of the shuttle in m/s^2. b) the speed of the shuttle in km/h after 74s.

A student pushes against a large maple tree with a force of magnitude 250 N. How much work does the student do on the tree? wouldn't it be zero. If not, what could be the right answer? W=F*D W=250*0 W=0

A camper does 7.4 x 102 J of work in lifting a pail filled with water 3.4 m vertically up a well at a constant speed. a)What force is exerted by the camper on the pail of water? b)What is the mass of water in the pail?