Text:

A 19-kg block is pulled along a level surface by a force of 142 N at an angle of 45°. The surface

has a coefficient of friction of 0.25.

Find: a) Normal force and frictional force.

b) Acceleration of the block.

c) Displacement of the block and its speed in a time interval of 13 s.

I’m confused because my answer is very different from the correct answer. Can anyone please point out what I am missing/doing wrong?

here is my solution, i worked backwards form the answers provided.

I cannot find the displacement, not too sure why

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Can you please explain why on the 1st step you did-

(mg-142xcos45)?

shouldn’t the normal force be only (42 x cos45)?

Because we have the mg force downwards which is 186N & we need to break the 142 into the x & y axis.

why do we need to subtract it from mg?

And if so, its more logical to me to add it to mg.