On a cold day, a heat pump absorbs heat from the outside air at 14°F (−10°C) and transfers it into a home at a temperature of 86
1 answer:
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Answer:
vB = 15.4 m/s
Explanation:
Principle of conservation of energy:
Because there is no friction the mechanical energy is conserve
ΔE = 0
ΔE : mechanical energy change (J)
K : Kinetic energy (J)
U: Potential energy (J)
K = (1/2)mv²
U = m*g*h
Where :
m: mass (kg)
v : speed (m/s)
h : hight (m)
Ef - Ei = 0
(K+U)final - (K+U)initial =0
(K+U)final = (K+U)initial
((1/2)mv²+m*g*h)final = ((1/2)mv²+m*g*h)initial , We divided by m both sides of the equation:
((1/2)vB² + g*hB = (1/2 )vA²+ g*hA
(1/2) (vB)² + (9.8)*(14.7) = 0 + (9.8)(26.8 )
(1/2) (vB)² = (9.8)(26.8 ) - (9.8)*(14.7)
(vB)² = (2)(9.8)(26.8 - 14.7)
(vB)² = 237.16
vB = 15.4 m/s : speed of the cart at B
Answer:
λ = 1360 m
Explanation:
Given data:
frequency of driving nails is given as 1 stroke per second mean at every 0.25 sec she hit the nails
speed of sound is given as 340 m/s
we know that the wave equation is given as
Speed = frequency × wavelength,
v = f × λ
where,
v = speed in meters/second (m/s)
f = frequency in Hertz (Hz)
substituing value to get wavelength of her driving nails
λ = 1360 m
The astronaut will move at 0.4 m/s in the opposite direction to the wrench
Explanation:
We can solve this problem by using the law of conservation of momentum. In fact, the total momentum of the astronaut-wrench system must be conserved before and after the launch.
Before the launch, the total momentum is zero, since the astronaut is at rest:
p = 0 (1)
After the launch, the total momentum is:
(2)
where :
m = 2 kg is the mass of the wrench
v = 10 m/s is the velocity of the wrench
M = 50 kg is the mass of the astronaut
V is the recoil velocity of the astronaut
Since momentum is conserved, we can write (1) = (2), and so we can solve for V:
And the negative sign means that the astronaut will move in the opposite direction to the wrench.
Learn more about conservation of momentum:
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