Answer:
A) 89.39 J
B) 30.39J
C) 23.8 J
Explanation:
We are given;
F = 30.2N
m = 3.5 kg
μ_k = 0.646
d = 2.96m
ΔEth (Block) = 35.2J
A) Work done by the applied force on the block-floor system is given as;
W = F•d
Thus, W = 30.2 x 2.96 = 89.39 J
B) Total thermal energy dissipated by the whole system which includes the floor and the block is given as;
ΔEth = μ_k•mgd
Thus, ΔEth = 0.646 x 3.5 x 9.8 x 2.96 = 65.59J
Now, we are given the thermal energy of the block which is ΔEth (Block) = 35.2J.
Thus,
ΔEth = ΔEth (Block) + ΔEth (floor)
Thus,
ΔEth (floor) = ΔEth - ΔEth (Block)
ΔEth (floor) = 65.59J - 35.2J = 30.39J
C) The total work done is considered as the sum of the thermal energy dissipated as heat and the kinetic energy of the block. Thus;
W = K + ΔEth
Therefore;
K = W - ΔEth
K = 89.39 - 65.59 = 23.8J
Answer:
0.94 m/s^2 downwards
Explanation:
m = 70 kg, m g = 70 x 9.8 = 686 N
R = 620 N
Let the acceleration be a, as the apparent weight decreases so the elevator is moving downwards with an acceleration a.
mg - R = ma
686 - 620 = 70 x a
a = 0.94 m/s^2
The answer is true hope that helped!!
First electromagnet
Explanation:
The first electromagnet is the strongest and it is stronger than the given electromagnet above.
An electromagnet is a temporary magnet made by passing current through a wire wounded round an iron core or metallic core.
- When current is passed through, the metal becomes magnetic.
- The strength of the electromagnet depends on the number of coil round the metal core and also the intensity of current passed through it.
- The higher the number of coils wounded round the metal core, the stronger the electromagnet that will be produced.
- Also, the higher the intensity of electricity passed through the wire, the stronger it is.
learn more:
Electromagnet brainly.com/question/2191993
#learnwithBrainly
The answer is dark energy. This is the energy in the universe that opposes the gravitational attraction of matter in the universe. Initially, cosmologists had thought that the universe was decelerating due to the gravitational attraction between matter in the universe after the big bang. However, using the Doppler shift effect, evidence was gathered on the nature of the expansion of the universe.
