help 17,18,19 17. A truck runs into a haystack and stops in 0.25 s A similar tru

Question

help 17,18,19

17. A truck runs into a haystack and stops in 0.25 s A similar truck runs into a wall and is stopped in 0.01 s. The force experienced by the driver in the haystack accident is how many times lower than the force on the driver that hit the wall? 625 times lower b. 25 times lower c Thhe same d. 25 times higher e 625 times higher 18. A1kg bob on a 10 m long pendulum is traveling a 10 m/s when it passes the lowest point. How high will the bob be above the lowest point when it stops and begins to swing in the opposite direction? b 51m c 3.7m e 0.75 19. How much work is done by sliding a 30 kg box up a 5 m ramp that has a base of 4 m? a. 1501 b 882 1 1176 1470 floor to go to class.

Explanation / Answer

17. truck was moving with same velocity then,

impulse = change in momentum , that will be same for both cases.

and impulse = F t

F1 (0.25) = F2 (0.01)

F1 / F2 = 1 / 25

Ans: (b) 25 times lower

18. Applying energy conservation,

PEi + KEi = PEf+ KEf

0 + m (10^2)/2 = m g h + 0

h = 10^2 / (2 x 9.8) = 5.1

Ans(b) 5.1 m

19. Work done = m g delta(h)

= 30 x9.8 x (5- 0)

= 1470 J

Ans(d)

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