Question

Physics


6. a 10 kg block is placed on a frictionless surface inclined at an angle of 30° from horizontal. what magnitude of horizontal force must be applied to hold the block stationary? *-fapplied


a.45.7 n


b.19.6 n


c.26.3n


d.35.7n


e.56.6 n

Answer 1

I’m not sure what the questioner needs.

I would like to establish a practice on Quora whereby people say WHAT IT IS THAT THEY ARE STUCK ON OR NEED HELP WITH.

This question is not hard to solve using the integrated form of Newton’s Second Law

F= M.A

We have the F. Stick the two or three or whatever masses together and we have the total mass that has to be accelerated by the force.

This gives you the acceleration of the whole mass.

Now use the Law again, but this time you have the acceleration A, and you rewrite the Law as

A = F/A or

————————————————

Acceleration ls force per unit mass.

So to find the force on any one of the blocks:

The force on it to achieve the acceleration you have established, simply multiply by its mass.

Now let’s have a closer look.

Using Newton’s third Law,

If the first block exerts a forward force on the second block, in this case of 60N, then the second block exerts an equal force of 60N back on the first block.

So the NET force on the first block is 100N - 60N = 40N.

The net force on the second block is of course just the 60N you will have already calculated by now.