Answer:
Part a)

Part b)


Part c)
equation of position in x direction is given as

equation of position in y direction is given as

Part d)

Part e)
H = 88.5 m
Part f)
t = 1.2 s
Explanation:
As we know that ball is projected with speed
v = 8.10 m/s at an angle 18 degree below the horizontal
so we will have




Part a)
Since it took t =4 s to reach the ground
so its initial y coordinate is given as



Part b)
components of the velocity is given as




Part c)
equation of position in x direction is given as

equation of position in y direction is given as

Part d)
distance where it will strike the floor is given as



Part e)
Height from which it is thrown is same as initial y coordinate of the ball
so it is given as
H = 88.5 m
Part f)
time taken by ball to reach 10 m below is given as


t = 1.2 s
Answer:

Explanation:
The work of force 2 will be given by the vectorial equation
. We know the value of
and have information about its movement, which relates to the net force
.
About this movement we can obtain the acceleration using the equation
. Since it departs from rest we have
.
And then using Newton's 2dn Law we can obtain the net force F=ma, thus we will have 
And we had the work done by force 2 as:

(The sign will be given algebraically since we take positive the direction to the right.)
With our values:

<em>Another (shorter but maybe less intuitive way for someone who is learning) way of doing this would have been to say that the work done by both forces would be equal to the variation of kinetic energy:</em>
<em>
</em>
<em>Which leads us to the previous equation straightforwardly.</em>
Answer:
20 N.
Explanation:
The following data were obtained from the question:
Mass of block B (m) = 2 Kg
Acceleration due to gravity (g) = 10 m/s²
Gravitational force (F) =..?
Force is simply defined as the product of mass and acceleration i.e
Force = mass (m) × acceleration (a)
F = ma
Thus, we can say that the gravitational force on block B will be the product of the mass of block B and acceleration due to gravity i.e
Gravitational force (F) = mass of block B (m) × acceleration due to gravity (g)
F = mg
Mass of block B (m) = 2 Kg
Acceleration due to gravity (g) = 10 m/s²
Gravitational force (F) =..?
F = mg
F = 2 × 10
F = 20 N
The, the gravitational force exerted on block B is 20 N