QUESTION 8 Petra pushes a crate across a rough floor. A frietional force of 28.0

Question

QUESTION 8 Petra pushes a crate across a rough floor. A frietional force of 28.0 N acts to oppose the motion of the crate, and Petra pushes with a horizontal force of 36.4 N. If the net work Petra does is 94.5 J, through what distance did she push the crate? O a 3.38 m O b. 2 650 m .11.3 m O d.2.60 m O e. 3 440 m QUESTION 9 A 5-kg object is moving to the right at 4 m/'s and collides with a 4-kg object moving to the left at 5 m/s. The objects collide and stick together. After the collision, the combined object: O a has the same kinetic energy that the system had before the collision. O b. has no kinetic energy O e has less than the system had before the collision. O d has more kinetic energy than the system had before the collision. QUESTION 10 A 525-g bullet is fired into a 360-g block of wood sispended as a ballistic pendulum. The combined mass swings up to a height of 8.75 em. What was the magnitude of the momentum of the combined mass immediately after the collision? a 0.471 kg m/s b.0.239 kg m/s G.0.626 kg m/s Click Saue and Submit to save and submit, Cick Save All Answers to sque oll onsoers MacBook Air 30

Explanation / Answer

8. friction force, f = 28 N

F = 36.4 N

W = 94.5 J

distance = x

W = F.x

x= W/F = 2.59615384 m

option d

9. m = 5 kg

u = 4m/s

M = 4 kg

v =- 5 m/s

collisde and stick togehter

after collsiion

5*4 - 4*5 = 9*v'

v' = 0

the iobject remains at rest

option b.

10. m = 5.25 g

M = 360 g

h = 8.75 cm

immidiately after collsion

momentum = (m + M)v

also

0.5(m + M)v^2 = (m + M)gh

v = sqrt(2gh)

p = (m + M)sqrt(2gh) = 0.4785 kg m/s

option e.

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