Answer:
Explanation:
Before it hits the ground:
The initial potential energy = the final potential energy + the kinetic energy
mgH = mgh + 1/2 mv²
gH = gh + 1/2 v²
v = √(2g (H - h))
v = √(2 * 9.81 m/s² * (0.42 m - 0.21 m))
v ≈ 2.0 m/s
When it hits the ground:
Initial potential energy = final kinetic energy
mgH = 1/2 mv²
v = √(2gH)
v = √(2 * 9.81 m/s² * 0.42 m)
v ≈ 2.9 m/s
Using a kinematic equation to check our answer:
v² = v₀² + 2a(x - x₀)
v² = (0 m/s)² + 2(9.8 m/s²)(0.42 m)
v ≈ 2.9 m/s
Answer:
3.33, 4.84
Explanation:
A) Actual coefficient of performance can be calculated by the formula stated below
Actual COP = heat delivered/ work required
Actual COP = 2,000/600
Actual COP = 3.33
B) Th = High temperature = 80°C + 273 = 353K
Tl = Low temperature = 7°C + 273 = 280K
The theoretical maximum coefficient of performance can ve calculated by the formula
Theoretical COP = Th/(Th-Tl)
Theoretical COP = 353/(353-280)
Theoretical COP = 353/73
Theoretical COP = 4.84
Answer:
3.13 m/s
Explanation:
From the question,
Since the flea spring started from rest,
Ek = W................... Equation 1
Where Ek = Kinetic Energy of the flea spring, W = work done on the flea spring.
But,
Ek = 1/2mv²............ Equation 2
Where m = mass of the flea spring, v = flea's speed when it leaves the ground.
substitute equation 2 into equation 1
1/2mv² = W.................... Equation 3
make v the subject of the equation
v = √(2W/m)................. Equation 4
Given: W = 3.6×10⁻⁴ J, m = 2.3×10⁻⁴ kg
Substitute into equation 4
v = √[2×3.6×10⁻⁴ )/2.3×10⁻⁴]
v = 7.2/2.3
v = 3.13 m/s
Hence the flea's speed when it leaves the ground = 3.13 m/s
Answer: Our body contains chemical potential energy from food we have eaten.
This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.
As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.
Explanation:
It is true that our food contains chemical bonds and these bonds have potential energy stored. So, when we eat food then our body acquires chemical potential energy.
When we rub our hands and arms then they form kinetic energy as atoms present within the skin of our hands come into motion. This rubbing of hands leads to the formation of heat which means thermal energy is being generated.
Thus, we can conclude that our body contains chemical potential energy from food we have eaten.
This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.
As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.
