Well, first of all, a car moving around a circular curve is not moving
with uniform velocity. The direction of motion is part of velocity, and
the direction is constantly changing on a curve.
The centripetal force that keeps an object moving in a circle is
Force = (mass of the object) · (speed)² / (radius of the circle)
F = m s² / r
We want to know the radius, to rearrange the formula to give us
the radius as a function of everything else.
F = m s² / r
Multiply each side by 'r': F· r = m · s²
Divide each side by 'F': r = m · s² / F
We know all the numbers on the right side,
so we can pluggum in:
r = m · s² / F
r = (1200 kg) · (20 m/s)² / (6000 N) .
I'm pretty sure you can finish it up from here.
The guy below is wrong!
F=ma
Where force = mass x acceleration
We dont have acceleration, a= change in velocity divided by the time taken.
a = v (final velocity) - u (initial) / t
a us 8-0 (at rest means u was 0) / 20 = 0.4
Using F=ma
F= mass x acceleration
F= 4 x 0.4
F=1.6 N
<h2>
Answer: 1000 J</h2>
The Work
done by a Force
refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.
It should be noted that it is a scalar magnitude, and its unit in the International System of Units is the Joule (like energy). Therefore, 1 Joule is the work done by a force of 1 Newton when moving an object, in the direction of the force, along 1 meter:
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:
(1)
When they are not parallel, both directions form an angle, let's call it
. In that case the expression to calculate the Work is:
(2)
For example, in order to push the 200 N box across the floor, you have to apply a force along the distance
to overcome the resistance of the weight of the box (its 200 N).
In this case both <u>(the force and the distance in the path) are parallel</u>, so the work
performed is the product of the force exerted to push the box
by the distance traveled
. as shown in equation (1).
Hence:
>>>>This is the work