1. Calculate the weight of a watermelon with a mass of 2 kg on the earth (g = 9.80 m/s2) and on the moon (g = 1.63 m/s2). Use this example to describe the differences between mass and weight and how mass and weight are related.

2. Apply Newton's second law to calculate the frictional force needed to hold a 0.02 kg pen in your fingers and keep it from falling. (g = 9.8 m/s2)

Question

Physics

Ray

15 February, 10:07

1. Calculate the weight of a watermelon with a mass of 2 kg on the earth (g = 9.80 m/s2) and on the moon (g = 1.63 m/s2). Use this example to describe the differences between mass and weight and how mass and weight are related.

2. Apply Newton's second law to calculate the frictional force needed to hold a 0.02 kg pen in your fingers and keep it from falling. (g = 9.8 m/s2)

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Mireya Duffy · Answer 1

Weight is a force, so we use newtons second law which states F=ma. So the weight of a watermelon on earth is 2kg x 9.81m/s², which is 19.62N (newtons). On the moon it weighs 2 x 1.63 which is 3.26N.

The weight of the pen is 0.02 x 9.81, which is 0.1962N. If the pen is not to fall the frictional force needs to be equal to this force, so the answer is 0.1962N.