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1. A 0.30-g pebble is held by a child whose feet are firmly planted on the groun

ID: 2139572 • Letter: 1

Question

1.     A 0.30-g pebble is held by a child whose feet are firmly planted on the ground. (a) Find the forces (magnitude and direction) exerted by the earth on the pebble and exerted by the pebble on the earth. (b) Calculate the magnitude of the acceleration of both the pebble and the earth when the pebble is released.

A 0.30-g pebble is held by a child whose feet are firmly planted on the ground. (a) Find the forces (magnitude and direction) exerted by the earth on the pebble and exerted by the pebble on the earth. (b) Calculate the magnitude of the acceleration of both the pebble and the earth when the pebble is released.

Explanation / Answer

a) for pebble F= 0.3E-3*9.81 =0.0029 N downwards

for earth F = 0.0029 N upwards


b) a pebble = 0.0029/0.3E-3 = 9.81 m/s^2

a earth = 0.0029/5.97E24=4.86E-28 m/s^2