A block of mass m = 7.30 kg (Assume h a = 5.50 m.) A skier of mass 67 kg is pull
ID: 1356681 • Letter: A
Question
A block of mass
m = 7.30 kg
(Assume ha = 5.50 m.)
A skier of mass 67 kg is pulled up a slope by a motor-driven cable.
(a) How much work is required to pull him 75 m up a 30° slope (assumed frictionless) at a constant speed of 1.5 m/s?
(b) What power (expressed in hp) must a motor have to perform this task?
Two objects (m1 = 4.65 kg and m2 = 3.30 kg) are connected by a light string passing over a light, frictionless pulley as in the figure below. The 4.65-kg object is released from rest at a point h = 4.00 m above the table.
(a) Determine the speed of each object when the two pass each other.
(b) Determine the speed of each object at the moment the 4.65-kg object hits the table.
(c) How much higher does the 3.30-kg object travel after the 4.65-kg object hits the table?
---------------------
Driving home from school one day you spot a ball rolling out into the street. You brake for 1.30 s, slowing your 900 kg car from 16.0 m/s to 9.50 m/s.
(a) What was the average force exerted on your car during braking?
Magnitude
(b) How far did you travel while braking?
these are the ones i was trying to follow using the book solutions, but it didn't explain well and up getting them wrong please help
Explanation / Answer
a) Using work energy theorem,
work done by gravity = change in KE
mg (deltaH) = mv^2 /2 - mu^2 /2
9.81 x (5.50 - 3.20) = v^2 /2 - 0
v = 6.72 m/s ..........At point B,
for point A to point C,
9.81 x (5.50 - 2) = v^2 /2 - 0
v = 8.29 m/s ..........At point C.
b) Work done by gravtitational force = mg (deltaH)
= 7.30 x 9.81 x (5.50 - 2) =250.65 J
Please Ask only One Question One Link.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.