Calculate: Block's Kinetic Energy, Work by Forces, & Gravity

AI Thread Summary
To calculate the kinetic energy and work done on a 5.4 kg block on a 37° incline, the initial kinetic energy is determined using the formula KE = 0.5 * m * v². The work done by the 75 N force is calculated using W = |F||D|cos(θ), resulting in 180 N*m. For the friction force, the participant attempts to use W = 25N * 5.2 * cos(θ) but encounters difficulties. The work done by gravity and the normal force also need to be calculated, with the final kinetic energy derived from the net work done. The discussion highlights challenges in applying the formulas correctly for each part of the problem.
Sportsman4920
Messages
16
Reaction score
0
A 5.4 kg block is pushed 3.0 m up a rough 37° inclined plane by a horizontal force of 75 N. If the initial speed of the block is 2.2 m/s up the plane and a constant kinetic friction force of 25 N opposes the motion, *calculate the following.
(a) the initial kinetic energy of the block
J
(b) the work done by the 75 N force
J
(c) the work done by the friction force
J
(d) the work done by gravity
J
(e) the work done by the normal force
J
(f) the final kinetic energy of the block
J
HELP!, please
 
Physics news on Phys.org
what have u done to answer them yourself?
 
W = |F||D|cos\theta theta being the angle between force and displacement vectors. That should take care of the first 5. The last one looks like W_{net} = \Delta KE
 
Last edited:
thank you
 
I tried to use the formula but I can't get the right answer.
 
how would you do part be on this question?
 
In part B the force is 75N the distance is 3m and the angle between them is 37 degrees, so using the formula the work should be 180 N*m
 
Thanks, now I'm trying to find the work done by friction. so I did W=25N*5.2(distance)*cos(theta but it didn't work
 
Back
Top