College Physics (7th Edition)

Published by Pearson
ISBN 10: 0-32160-183-1
ISBN 13: 978-0-32160-183-4

Chapter 4 - Force and Motion - Learning Path Questions and Exercises - Exercises - Page 136: 24


$a).$ (3) two $b).$ 1470N, 735N.

Work Step by Step

a). There are two forces acting on the crate: the weight and the normal force. The normal force is such that its difference with weight gives the crate upward acceleration. b). N+w=ma N=$ma-w=ma-mg=m(a-g)=75(9.8+9.8)=1470N$ [we take upwards as positive] On the ground, the normal force would be equal in magnitude to the weight $N=-w=-mg=735N$
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