Physics Practical Problems of Dynamics Q9

Practice Question Solving
1

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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?

2

here is my solution, i worked backwards form the answers provided.
I cannot find the displacement, not too sure why :woman_shrugging:

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3

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.