Physics.simple force ques

Question

a horizontal force of 4N acts on a wooden block hwhich is stationary and of mass 0.4 kg on a smoth horizontal surface . wats the velocity of the block aft 2 seconds?

how exactly do i count this?i know its F=MA

so is it smth like 4N-FRICTION=(O.4)(0) for acceleration as its stationary.simple explanation is vry much appreciated XD

Answer 1

Force F = 4 N

Mass m = 0.4 kg

Acceleration a = F/m = 4/0.4 = 10 m/s2

Initial velocity u = 0

Time t = 2 s

Final velocity v = ?

v = u + at

= 0 + 10 * 2

= 20 m/s

Note: - The problem says that the horizontal surface is smooth. Therefore, you can neglect friction.

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Answer 2

Hey, for some reason it won't let me answer your other question so here it is.

Alright, I didn't even read the second part to your question, 'the vehicle stops at 250m.' This means there MUST have been acceleration. This question is kind of confusing because it first states the vechicle was moving at a constant velocity and then suddenly decreases speed (deacceleration) to a stop. They probably missed the part where it says the vechicle drives into a muddy/rocky road or w/e.

So to do this...

Fnet = ma (because there is acceleration)

Find the acceleration, the above poster I think is correct (I can't recall the kinematic equations, so find acceleration using one of them). Vf (final velocity) is 0 because it comes to a stop. Vi (inital velocity) is 5m/s, distance is 250m and you solve for acceleration.

Then you know:

Fnet = ma

Fa - Ff = ma (it is Fa (-Ff) because they are in opposite directions)

So now you have:

Fa - Ff = ma (you are trying to find Ff)

-Ff = ma - Fa

Ff = Fa - ma

Ff = fgsin(theta) - ma

Ff = (1800kg)(9.8m/s^2)(sin180) - (1800kg)(acceleration)

Ff =

(sin 180 because it is a horizontal road)

This should give you the answer!

Goodluck.

Answer 3

F = ma

a = F/m

a = 4N/0.4kg

a = 10 m/s^2

Vf = Vi + at

Vf = 0 + (10 m/s^2)(2 s)

Vf = 20 m/s      ANSWER

Hope this helps.

teddy boy

Answer 4

4 = 0.4 A, so A is 10 meters per second per second.  After two seconds, the velocity will have changed by 20 meters per second.