Answer:
4.7 × 10⁵J
Explanation:
E = I * a * t
80% = 0.80
25cm = 0.25m
52cm = 0.52m
0.90h = 3240s
E = (0.80)(1400)(0.25 * 0.52)(3240)
= 4.7 * 10⁵J
Answer: A
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Answer:
The time of short pulse of light beam is 
Explanation:
Given that,
A beam of light from a laser illuminates a glass.
Suppose, the length of piece is 
Index of refraction is 2.83.
We need to calculate the speed of light pulse in glass
Using formula of speed

Put the value into the formula


We need to calculate the time of short pulse of light beam
Using formula of velocity


Put the value into the formula


Hence, The time of short pulse of light beam is 
Answer:
Inclined plane.
Explanation:
Geometrically, a screw is a narrow inclined plane that is wrapped around a cylinder. Like the other simple machines a screw can amplify force; a small rotational force (torque) on the shaft can exert a large axial force on a load.
A screw is a cylinder with a head (solid top) at one end and a pointed tip (like a nail) at the other end.
The mechanical advantage of the screw depends on the space between the threads and the length (and thickness) of the screw. The closer the threads are, the greater the mechanical advantage. It is easier to drive a screw into an object if the thread spacing is smaller.