Question

A 3.5 kg block is pushed along a horizontal floor by a force of magnitude 15 N at an angle è = 40° with the horizontal. The coefficient of kinetic friction between the block and the floor is 0.25. Calculate the magnitudes of (a) the frictional force on the block from the floor and (b) the block's acceleration.

Answer 1

(a) Friction= u * Normal
Friction= 0.25 * Normal
Normal=15*sin(40) + mg = 43.94
Friction= 0.25 * 43.94 = 10.985N

(b) 19*cos(40) - 10.985 = 0.5 N
F =ma
0.5N = 3.5kg * a
a = 0.14 m/s^2

Answer 2

correction on the above answer. It should say 15*cos(40) for part B.

Answer 3

Thanks for the help guys, i have finally figured out this question after 8 years. I think I will pass my physics class this time around.

Answer 4

This honestly is the best thing I've gotten out of physics so far. Made my day. Thank you Don.