Question

Solve this:

13. How much is the viscous drag acting on a rocket-driven sled that is going at constant speed against a frictional force of 22000 newtons when the thrust of the engine is 31000 newtons—
(a) 8500 N (b) 9000 N
(c) 9500 N (c) 9500 N

14. To slow down a car, a braking force of 1200 newtons is applied for 10 seconds. How much force would be needed to produce the same change in yelocity in 6 seconds —
(a) 2000 N (b) 3000 N
(c) 2500 N (d) 1500 N

15. A frictionless wagon is pushed from rest, with a force of 60 newtons for 14 seconds. If it then strikes a wall and comes to rest in 0.15 second, how much average force does the wall exert on it ?
(a) 6000 N (b) 5600 N
(c) 4500 N (d) 4000 N

Answer 1

Dear student,
Here is the solution of your asked query:
Q.15. Here, the following condition must be applied
Impulse that puts the wagon in motion=Impulse that stops the wagon
60 x 14=F x 0.15
or F=(60 x 14)/0.15
=5600 N
Thus, the average force that the wall exert on the wagon is 5600 N.

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