Answer:
28.8 %
Explanation:
The efficiency of an engine is given by:
where
W is the useful work done
is the heat in input
For this machine, we have
W = 15.0 kJ is the work done
is the heat exchausted to the cold reservoir, so the total amount of heat in input is
And so the efficiency is
which corresponds to 28.8 %.
Since his line of sight 63 degrees makes with the tip of the building
Tan63° = height of building / Horizontal distance
tan63° = Height / 50
50tan63° = Height
Height = 50tan63°
Height ≈ 50*1.9626
Height ≈ 98.13 m
Height of the building is ≈ 98.13 m. Mind you in solving for this height we have neglected the height of Daniel.
The height of building actually should be 98.13 m plus the height of Daniel. Since the 63° was measured from his eye level.
Answer: a. F doubled
b. F reduced by one-quarter i.e
1/4*(F)
c. 1/9*(F)
d. F increased by a factor of 4 i.e 4*F
e. F reduces 3/4*(F)
Explanation: Coulombs law states the force F of attraction/repulsion experience by two charges qA and qB is directly proportional to thier product and inversely proportional to the square of distance d between them. That is
F = k*(qA*qB)/d²
a. If qA is doubled therefore the force is doubled since they are directly proportional.
b. If qA and qB are half, that means thier new product would be qA/2)*qB/2 =qA*qB/4
Which means the product of charge is divided by 4 so the force would be divided by 4 too since they are directly proportional.
c. If d is tripped that is multiplied by 3. From the formula new d would be (3*d)²=9d² but force is inversely proportional to d² so instead of multiplying by 9 the force will be divided by 9
d. If d is cut into half that is divided by 2. The new d would be (d/2)²=d²/4. So d² is divided by 4 so the force would be multiplied by 4
e. If qA is tripled that is multiplied by 3. F would be multiplied by 3 also, if at the same time d is doubled (2*d)²= 4*d² . Force would be divided by 4 at same time. So we have,
3/4*F
Answer:
a) battery-->electrical current-->copper wire rotor -->magnet--> mechanical energy
Explanation:
