Question

Judy is pulling on a trunk with a 12-N force. Ike pulls at right angles to Judy. With how much force must Ike pull to make the resultant force on the trunk 20 N? Round answer to one decimal place.

Answer 1

To understand the problem, let's first draw a free body diagram of the forces exerted by Judy and Ike on the truck. (Refer to the left side of the attachment).

To solve for the resultant, we just use the tip-to-tail method. This is illustrated on the right side of the attachment.

We can see that the tip-to-tail method forms a right triangle thus we can just apply the Pythagorean theorem in solving for Ike's force.

$20^{2} = 12^{2} + F^{2}$
$400 = 144 + F^{2}$
$256 = F^{2}$
$F = 16.0$

ANSWER: Ike must pull the truck with a force of 16.0 N.