Answer:
a. 45 N. / b. 0.08 m/s^2. / c. 102 N
F = ma
F = 15(3)
F = 45 newtons
F/m = a
20/250 = a
0.08 m/s^2 = a
R = ma
R =1.5(68)
102 N
The work done by a constant force in a rectilinear motion is given by:

where F is the magnitude of the force, d is the distance and θ is the angle between the force and the displacement vector.
In this case we have two forces then we need to add the work done by each of them; for the first force we have a magnitude of 17 N, a displacement of 12 m and and angle of 0° (since both the displacement and the force point right); for the second force we have a magnitude of 36 N, a displacement of 12 m and an angle of 30°. Plugging these values we have that the total work is:

Therefore, the total work done is 578.123 J and the answer is option E
Assuming that all the bullet’s energy heats the paraffin, its final temperature is 27.1 degree C. The correct option is D.
<h3>What is temperature?</h3>
Temperature is the degree of hotness and coldness of the material.
The energy of the bullet E = 1/2 mv²
E = 1/2 x 10 x 10⁻³ x (2000)²
E = 2 x 10⁴ J
This heat is used in heating the paraffin
E = m x c ΔT = m x c (Tfinal -Tinitial)
2 x 10⁴ J = 1 x 2.8 x 10³ x (Tfinal -20)
Tfinal = 27.1°C
Thus, the final temperature is 27.1 degree C. The correct option is D.
Learn more about temperature.
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knowledge of first aid ... eg St John Ambulance, Red Cross etc. I think that everyone in a school should be taught First Aid.
Answer:

Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
<h3>P.E. = mgh </h3>
Where,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
<h3>Work done = mgh</h3>
Work done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
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