Answer:
it will take
to reach its final rotating speed
Explanation:
Let initially the turntable is at rest
So its initial angular velocity will be 
Let the turn table is rotating with an angular acceleration 
According to first equation of motion
We know that
, here
So 
So it will take
to reach its final rotating speed
A polar molecules have charges that are free to move around
Answer:
work done will be equal to 305.05 J
Explanation:
We have given force exerted F = 45 N
Angle with the horizontal 
Distance moved due to exerted force d = 9.1 m
Work done is equal to
, here F is force
is angle with horizontal and d is distance moved due to force
So work done 
So work done will be equal to 305.05 J
<h2>
Answer:</h2>
(a) 10N
<h2>
Explanation:</h2>
The sketch of the two cases has been attached to this response.
<em>Case 1: The box is pushed by a horizontal force F making it to move with constant velocity.</em>
In this case, a frictional force
is opposing the movement of the box. As shown in the diagram, it can be deduced from Newton's law of motion that;
∑F = ma -------------------(i)
Where;
∑F = effective force acting on the object (box)
m = mass of the object
a = acceleration of the object
∑F = F - 
m = 50kg
a = 0 [At constant velocity, acceleration is zero]
<em>Substitute these values into equation (i) as follows;</em>
F -
= m x a
F -
= 50 x 0
F -
= 0
F =
-------------------(ii)
<em>Case 2: The box is pushed by a horizontal force 1.5F making it to move with a constant velocity of 0.1m/s²</em>
In this case, the same frictional force
is opposing the movement of the box.
∑F = 1.5F - 
m = 50kg
a = 0.1m/s²
<em>Substitute these values into equation (i) as follows;</em>
1.5F -
= m x a
1.5F -
= 50 x 0.1
1.5F -
= 5 ---------------------(iii)
<em>Substitute </em>
<em> = F from equation (ii) into equation (iii) as follows;</em>
1.5F - F = 5
0.5F = 5
F = 5 / 0.5
F = 10N
Therefore, the value of F is 10N
<em />
C) In the absence of an unbalanced force, an object at rest will stay at rest and an object in motion will stay in motion.
hope this helps and have a great day :)