An eartly method of measuring the speed of light makes use of a rotating slotted wheel.
A beam of light passes through one of the slots at the outside edge of the wheel, travels to a distant mirror, and returns to the wheel just in time to pass through the next slot in the wheel. One such slotted wheel has a radius of 5.0 cm and 500 slots around its edge. Measurements taken when athe mirror is L = 550 m from the wheel indicate a speed of light of 3.0 x 10^8 km/s.

(a) What is the (constant) angular speed of the wheel?
(b) What is the linear speed of a point on the edge of the wheel?

Explanation:

Distance traveled by light = 2 x 550 m = 1100 m

time taken by light to travel this distance = 1100 / 3 x 10⁸

=  366.67 x 10⁻⁸ s

angle between two consecutive slots = 2π / 500 rad

= .004π

angular velocity of wheel = angle moved / time taken

= .004π / 366.67 x 10⁻⁸

= 1091π radian / s

b )  linear speed of a point on the edge of the wheel

= ω R , r is radius of wheel , ω is angular velocity.

= 1091π x 5 x 10⁻²

= 1712.8 m /s

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.

chemical energy --> gravitational potential energy --> kinetic energy --> elastic potential energy --> gravitational potential energy

explanation:

when emma starts the hike, the chemical energy stored in her body is used to climb up the mountain, and so she gains gravitational potential energy (because at the end, she will be at a higher height h above the ground). then she goes bungee jumping: as she falls, this gravitational potential energy is converted into kinetic energy (because her speed increases as she falls down), until the point when the rope stretches, and she stops moving. at that moment, all the kinetic energy is converted into elastic potential energy due to the stretching of the rope. then, this energy is released because the rope returns to its natural length, and emma gains a small increase in altitude , so she gains some gravitational potential energy.