Please help with all parts. Thank you!! A 4-kg box is pushed to the right by a f

Question

Please help with all parts. Thank you!!

A 4-kg box is pushed to the right by a force of 4 N for a distance of 24 m. It has an initial velocity of 4 m/s to the right.
NOTE: Since this problem gives the DISTANCE x traveled, FIRST look at kinetic energy and calculate the NET WORK using Wnet = F x = K. After the kinetic energy values are calculated, then calculate the momenta and impulse values. Remember that on quiz and test problems, you will need to decide which values should be calculated first.

What is the initial momentum pi of the box?
kg m/s

What is the impulse or change in momentum p of the box?
kg m/s

What is the final momentum pf of the box?
kg m/s

What is the initial kinetic energy Ki of the box?
J

What is the change in kinetic energy K of the box?
J

What is the final kinetic energy Kf of the box?
J

How long t does it take for the box to travel the distance of 24 m?
s

B) The table has a height of 1.25 m, and the initial speed of ball A is vA0=2.9 m/s. What is ball A's speed just before it hits the floor?

C) At what distance from the table's edge will ball A hit the floor?

D) A car moving at speed of 5.0 m/s crashes into an identical car stopped at a light. What is the speed (in m/s) of the wreckage immediately after the collision, assuming the cars stick together?

Explanation / Answer

1)

given
m = 4 kg
F = 4 N
d = 24 m
vi = 4 m/s
a) initial momentum, Pi = m*vi

= 4*4

= 16 kg.m/s

b) Workdone = change in kinetic energy

F*d = (1/2)*m*(vf^2 - vi^2)

4*24 = (1/2)*4*(vf^2 - 4^2)

48 = vf^2 - 16

==> vf = sqrt(48 + 16)

= 8 m/s

so, delta_P = m*(vf - vi)

= 4*(8 - 4)

= 16 kg.m/s or N.s

c) Pf = m*vf

= 4*8

= 32 kg.m/s

d) Ki = (1/2)*m*vi^2

= (1/2)*4*4^2

= 32 J

e) delta_K = Workdone

= F*d*cos(0)

= 4*24

= 96 J

f) Kf = Ki + W

= 32 + 96

= 128 J

g) impulse = change in momentum

F*delta_t = 16

delta_t = 16/F

= 16/4

= 4 s

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.