1. Two 20.-newton forces act concurrently on an object. What angle between these forces will produce a resultant force with the greatest magnitude?

Question

(1) 0°
(2) 45°
(3) 90.°
(4) 180.°
2. A rock is thrown straight up into the air. At the highest point of the rock’s path, the magnitude of the net force acting on the rock is
(1) less than the magnitude of the rock’s weight, but greater than zero
(2) greater than the magnitude of the rock’s weight
(3) the same as the magnitude of the rock’s weight
(4) zero

And can you please explain why? Thanks.

Answer 1

1. F max = 20 + 20 = 40 N. @ 0o.

2. The velocity is zero and not
changing; therefore, the acceleration is zero also. F = M*a = M*0 = 0.

Answer 2

45