Aroller coaster car sits at rest at the top of 40 m hill (y = 40 m). the zero line for this problem is located at the bottom of the hill (y = 0). a) what is the change in potential energy as car moves from point a to point b? b) what is the speed of the car at the bottom of the hill? c) what is the speed of the car when it reaches point b? d) the car is released from point a again, but this time it only reaches a height of 25.0 m above the reference point. if the mass of the car is 1000 kg and the car travelled a distance of 400 m, estimate the magnitude of the frictional force between the car and the track.

Newton's law of universal gravitation states that the force f between two masses, m1 and m2, is given below, where g is a constant and d is the distance between the masses. find an equation that gives an instantaneous rate of change of f with respect to d. (assume m1 and m2 represent moving points.)

Abatter hits the baseball a with an initial velocity of v0 = 110 ft/sec directly toward fielder b at an angle of 23° to the horizontal; the initial position of the ball is 2.2 ft above ground level. fielder b requires 0.44 sec to judge where the ball should be caught and begins moving to that position with constant speed. because of great experience, fielder b chooses his running speed so that he arrives at the “catch position” simultaneously with the baseball. the catch position is the field location at which the ball altitude is 8.4 ft. determine the velocity of the ball relative to the fielder at the instant the catch is made.

Which of the following is a homogenous mixture? o a. a toy box filled with toys o b. blood o c. trail mix o d. spaghetti and meatballs submit