Answer:
Thus, the payback time for cavity wall insulation is 7.5 years
Answer:
Speed at which the ball passes the window’s top = 10.89 m/s
Explanation:
Height of window = 3.3 m
Time took to cover window = 0.27 s
Initial velocity, u = 0m/s
We have equation of motion s = ut + 0.5at²
For the top of window (position A)
For the bottom of window (position B)
We also have
Solving
So after 1.11 seconds ball reaches at top of window,
We have equation of motion v = u + at
Speed at which the ball passes the window’s top = 10.89 m/s
Answer:
If child weight is equal to rope force then child will move with uniform speed
or we can say that the child will remain at rest in his position
Explanation:
As we know that child is hanging by rope
so here there will be two forces on the child
1) Weight or gravitational force which act vertically downwards
2) Tension in the rope which act vertically upwards
Now if child will accelerate upwards then tension force must be more than the weight of the child
If tension force is less than the weight then child will decelerate and his speed will decrease
if tension force is equal to child weight then in that case the child will remain at rest or it will move with same speed
Input work = 9.63×10³ J.
Output work = 3.0×10³ J
By definition,
Efficiency = (Output work)/(Input work)
= (3.0×10³)/(9.63×10³)
= 0.31 = 31%
Answer: 31%
The 1st one is basically B because it will stay in motion with the same speed and in the same direction unless acted on by an unbalanced force and the 2cd one is A because most of is transformed into thermos energy. hope this helps!
