A ball is thrown straight up from a point 2 m above the ground. The ball reaches a maximum height of 3 m above its starting poin
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Answer:
hydropower
Explanation:
hydroelectric power is a domestic source of energy. This automatically allows each state to produce their own energy without being reliant on international fuel sources. It also won't pollute the air like power plants that burn fossil fuels, such as coal or natural gas. This is because it is powered by water.
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Answer:
Part A: 7.75 m/s
Part B: 2330.8 kN
Part C: 24.03 kN
Part D: 4.8 kN
Part E:
Part F: Option D
Bending his legs increases the time over which the ground applies force, thus decreasing the force applied by the ground.
Explanation:
<u>Part A </u>
From the fundamental kinematic equation
where v is the velocity of the man just before hitting the ground, g is acceleration due to gravity, u is initial velocity, h is the height.
Since the initial velocity is zero hence
Substituting 10 m/s2 for g and 3 m for h we obtain
<u>Part B </u>
Force exerted by the leg is given by
F=PA where P is pressure, F is force, A is the cross-section of the bone
Substituting 2.3 cm which is equivalent to 0.023m for d and for P we obtain the force as
<u>Part C </u>
The fundamental kinematic equation is part (a) can also be written as
and making a the subject then
where a is acceleration and
is the change in length
Substituting the value obtained in part a, 7.75 m/s for v, u is zero and 1cm which is equivalent to 0.01 m for then
Force exerted on the man is given by
<u>Part D </u>
The fundamental kinematic equation is part (a) can also be written as
and making a the subject then
where a is acceleration and
is the change in height
Also, force exerted on the man is given by
Substituting 80 Kg for m, 50 cm which is equivalent to 0.5m for \triangle h and other values as used in part c
<u>Part E </u>
Part F
Bending his legs increases the time over which the ground applies force, thus decreasing the force applied by the ground