A small box with a weight or 30.0 N is placed on top of a larger box that has a
ID: 1529936 • Letter: A
Question
A small box with a weight or 30.0 N is placed on top of a larger box that has a weight of 65.0 N. The system of two boxes is at rest on a horizontal surface (the larger box is in contact with the surface). You apply an additional downward force of 20.0 N to the top of the small box by resting your hand on it. For this problem, use g = 10 N/kg. What is the magnitude of the force exerted on the large box by the small box? 50 What is the magnitude of the force exerted on the large box by the surface? 115 N Now, imagine that the horizontal surface Is the floor of an elevator, and the boxes arc in the elevator, which has an acceleration directed downward of 3.00 m/s^2. What is the magnitude of the force exerted on the large box by the small box in this case? 41 What is the magnitude of the force exerted on the large box by the surface In this case? 95.5Explanation / Answer
d)The force exerted on the large box is the reaction of the force that the system of two boxes plus the 20 N exerts on floor.
F' = F + m(g - a) + M(g - a)
m = 30/10 = 3 and M = 65/10 = 6.5 ; a = 3 ; g = 10 and F = 20
F' = 20 + 3(10 - 3) + 6.5 (10 - 3) = 86.5 N
Hence, F' = 86.5 N