Establishing a high critical value when calculating the results of a statistical test means that a researcher will have more con
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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
Define sources of energy
Energy is the capacity of a body to do work.
We Classify the sources of energy on the basis of:
<u>Occurence:</u>
- Natural Sources: Natural energy sources are those which are made available to us by nature. Solar energy, wind energy, energy from water (hydro energy) are some of such natural sources of Energy.
- Synthetic Sources: Synthetic energy are those that use man-made materials as sources of energy. Fir example, chemical energy, stored in the batteries, (used in calculators, watches, etc.) is a synthetic source of energy.
<u>Physical</u><u> </u><u>State:</u>
- Solid: Firewood, Charcoal, coal are examples of solid fuels.
- Liquid: Kerosene, Petrol & diesel are all liquid fuels.
- Gas: Petroleum gas, commonly used as LPG (Liquified Petroleum Gas), & natural gas, also used CNG (Compressed Natural Gas), are examples of gaseous fuels
<u>Availability</u><u>:</u>
- Renewable: A renewable source of energy is a natural resource that can replenish itself naturally over a short period of time. Wind, sun, biomass (from plants) & hydropower (from water) are all renewable sources of energy. These arr inexhaustible natural resources.
- Non-renewable: Energy sources which get us & cannot be replaced or replenished in a short period of time are called non-renewable sources of energy. These are also called exhaustible natural resources. Fossil fuels, (like petroleum, natural gas & coal), are non-renewable sources of energy.