work done by gravity is mgh where h is the increase in altitude.
here h = 8.1 sin 14.6
h = 2.04 meters
so
U = 10.2 kg * 9.8 m/s^2 * 2.04m = 100 N *2.04 meters = 204 J
work done by friction = friction forcve in Newtons * 8.1 meters
friction force = .39 * 100 N *cos 14.6 = 37.7 Newtons
37.7 * 8.1 = 306 Joules
A 10.2 kg crate is pulled up a rough incline
with an initial speed of 1.5 m/s. The pulling
force is 123.0 N parallel to the incline, which
makes an angle of 14.6◦ with the horizontal.
The coe�cient of kinetic friction is 0.39 and
the crate is pulled a distance of 8.1 m.
The acceleration of gravity is 9.81 m/s2 .
a) Find the work done by Earth’s gravity
on the crate. Answer in units of J.
017 (part 2 of 5) 10.0 points
b) Find the work done by the force of friction
on the crate. Answer in units of J.
1 answer
1 answer