Answer:
(a) 
(b) 
(c) K.E. = 21.168 J
(d) 
Explanation:
Given:
- mass of a block, M = 3.6 kg
- initial velocity of the block,

- constant downward acceleration,

That a constant upward acceleration of
is applied in the presence of gravity.
∴
- height through which the block falls, d = 4.2 m
(a)
Force by the cord on the block,



∴Work by the cord on the block,


We take -ve sign because the direction of force and the displacement are opposite to each other.

(b)
Force on the block due to gravity:

∵the gravity is naturally a constant and we cannot change it


∴Work by the gravity on the block,



(c)
Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.
mathematically:


K.E. = 21.168 J
(d)
From the equation of motion:

putting the respective values:

is the speed when the block has fallen 4.2 meters.
Answer:
3 N to the right
Explanation:
There are two forces acting on the car:
- A force of 10 N towards the right
- A force of 7 N towards the left
Therefore, the net force is given by the difference between the two, since they are in opposite directions:

And the direction is to the right, since the force to the right has greater magnitude than the force to the left.
Answer:
one im so sry i have no idea. I have been researshing for about 30min and i cant find anything im so sry:/
Explanation:
Answer:3.51
Explanation:
Given
Coefficient of Friction 
Consider a small element at an angle \theta having an angle of 
Normal Force

Friction 

and 






