The kilogram is the SI unit of mass and it is the almost universally used standard mass unit. The associated SI unit of force and weight is the Newton, with 1 kilogram weighing 9.8 Newtons under standard conditions on the Earth's surface.
Acceleration is given by:

where
v is the final velocity
u is the initial velocity
t is the time interval
Let's apply the formula to the different parts of the problem:
A) 
Let's convert the quantities into SI units first:


t = 4.0 min = 240 s
So the acceleration is

B) 
As before, let's convert the quantities into SI units first:


t = 94 s
So the acceleration is

C) 
For this part we have to use a different formula:

where we have
v = 0 is the final velocity
u = 89.2 m/s is the initial velocity
a is the acceleration
d = 75 m is the distance covered
Solving for a, we find

Answer: Normal force, N = 141.64 Newton
Explanation:
All the forces acting on the system and described in free body diagram are:
1) gravitational pull in downward direction
2) Normal force in upward direction
3) External force of 40 N acting at an angle of 37° with the horizontal can be resolved in two rectangular components:
i) F Cos 37° along the horizontal plane in forward direction and
ii) F Sin 37° along the vertical plane in downward direction
Applying the Newton's second law, net forces in the vertical plane are:
Net force, f = N - (mg + F Sin 37°)
As there is no acceleration in the vertical plane hence, net force f = 0.
So,
N - (mg + F Sin 37°) = 0
Adding (mg + F Sin 37°) both the sides in above equation, we get
N = mg + F Sin 37°
N = 12
9.8 + 40
0.601 because (Sin 37° = 0.601)
N = 117.6 + 24.04
N = 141.64 Newton
Since the stone is being dropped, you know that it is in free fall. That means you can use your kinematics equations, since acceleration is free fall is a constant 9.8 m/s^2 down.
Looking through the kinematics equations, you want to use one that lets you find t, time, while using variables that we already know the values of. Notice that in the equation:

Say that the rock starts at point x=0. That means the initial value of x, the position, is

= 0m, and the final position is

= -4.9m. We are also told that the initial velocity,

= 0, assuming it's being dropped from rest, and a = -9.8 m/s^2. Plug these numbers in and solve for t:

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Answer: t = 1 s
Answer:
1355 days
Explanation:
Find the given attachment