All of the above can affect the resistance of a metal
(A) A device that converts heat into work with 100% efficiency
It clearly violates the second law of thermodynamics because it warns that while all work can be turned into heat, not all heat can be turned into work. Therefore, despite the innumerable efforts, the efficiencies of the bodies have only been able to reach 60% at present.
Answer:
The frequency of the standing wave in the second case is higher than that in the first case
Explanation:
The frequency and wavelength of a wave are related.
The moment you sliced the bottle, you've reduced the wavelength of the bottle.
When wavelength decreases, frequency increases and vice versa.
So, When frequency
increases in the second case, more wave crests pass a fixed point each second. That means
the wavelength shortens. So, as frequency increases, wavelength
decreases. The opposite is also true—as frequency decreases,
wavelength increases.
Answer:
Explanation:
Given that,
The spring constant
K = 1N/m
Frequency of motion
f = 14Hz
We want calculate the mass m?
The frequency of spring system is related to the mass by
From w = √k/m
Where w = 2πf
f = 1/2π √k/m
Where,
w is angular frequency in rad/s
m is mass of object attached in kg
k is the spring constant in N/m
f Is the frequency in Hz
Then, make m subject of formula
Multiply both sides by 2π
2πf = √k/m
Square both sides
4π²f² = k/m
Then, k= 4π²f² × m
m = k / 4π²f²
m = 1 / (4π² × 1.4)
m = 1 / 55.27
m = 0.0181 kg
m= 18.1 g
The mass of the object attached in 18.1 g or 0.0181 kg
Answer:
The answer is C.move forward rapidly until stopped.
Explanation:
50 miles an hour is a very high speed. The momentum transfer to the car at stop light will move the car forward rapidly until its brake is able to stop it.
