Answer:
a) t = 4.14 s
b) Speed with which it hits the ground = 40.58 m/s
Explanation:
Using the equations of motion,
g = 9.8 m/s², y = H = 84 m,
Initial velocity, u = 0 m/s,
final velocity, v = ?
Total Time of fall, t = ?
a) y = ut + gt²/2
84 = 0 + 9.8t²/2
4.9t² = 84
t² = 84/4.9
t = 4.14 s
b) v = u + gt
v = 0 + (9.8 × 4.14)
v = 40.58 m/s
As we know that total work done by a force is given by
so it is product of force and displacement along same direction
as we can write it as
so it must be the product of force and displacement in same directions so correct answer must be
<u>B. in the same direction as the displacement vector and the motion.</u>
The rise in temperature is 0.49°c
<h3>What is specific heat capacity?</h3>
The quantity of heat energy needed to raise a substance's temperature per unit of mass is known as specific heat capacity. A material's specific heat capacity is a physical characteristic. Since its value is inversely correlated with the size of the system under study, it is also an illustration of an extended feature.
<h3>what is law of conservation of energy?</h3>
Energy can only be transformed from one form to another. It cannot be created or destroyed
<h3>How will this question be solved?</h3>
From law of conservation of energy we know,
Potential energy of the block= cmΔT
mgh= cmΔT
m×9.8×20= 400×m×ΔT
196=400ΔT
ΔT=0.49°C
To know more about specific heat capacity visit:
brainly.com/question/2530523
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It takes 365 1/4 days for the Earth to complete 1 full revolution.
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