Impulse = (force) x (time)
The first impulse was (20 N) x (10 sec) = 200 meters/sec
The second one is (50 N) x (time) and we want it equal to the first one, so
(50 N) x (time) = 200 meters/sec
Divide each side by 50N : Time = 200/50 = 4 seconds
By the way, the quantity we're playing with here is the cart's momentum .
To produce an impulse of equal magnitude to a 20- Newton force acting for 10 seconds, a 50-Newton force must act for 4 seconds, according to Newton's second law of motion in terms of momentum. ;
The time for which a 50-newton force must act to the right to produce an equal impulse to a 20-newton force acting to the left for 10 seconds is 4 seconds. This is calculated using the formula for impulse. Both impulses must be equal for the forces acting on the cart.
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