Answer:
The centripetal acceleration is 6.95 m/s²
Explanation:
Given;
angular displacement of the blade, θ = 90.08⁰
duration of motion of the blade, t = 0.4 s
radius of the circle moved by the blade, r = 0.45 m
The angular speed of the blade in radian is calculated as;

The centripetal acceleration is calculated as;
a = ω²r
a = (3.93)² x 0.45
a = 6.95 m/s²
In a parallel circuit, the total resistance calculated from the individual resistances is computed from the formula: 1/Rt = 1/R1 + 1/R2. substituting R1 and R2, then
1/Rt = 1/7 + 1/49
1/Rt = 1/6.125 = 1/ 49/8
Rt = 49/8 <span>Ω
The total resistance hence is </span>49/8 Ω
Answer: d)
Explanation: In order to justify the answer we have to consider that the energy of photons directely depent on the frequency so the energy is inverselly dependent of the wavelegth.
If both beams have the same power, this means Energy/time so the number of photons per second must be different. As consequence a) is wrong as b) since it is not posible since UV photon have more energy that IR photons. c) It is no necessary know the frequency since the wavelength is related in the form:
c=λν c is the speed of light, λ the wavelegth and ν the frequency.
d) Certainly will be more more IR photons than UV photons to get the same beam power.
The average speed of a moving object is the rate of change of a certain distance with respect with time. It is equal to the total distance that was traveled by the object over the total time it takes to travel that distance. For this problem we need to assume that the total distance that was traveled would be equal to 120 miles. So, for the first half of the distance or 60 miles at a speed of 30 miles per hour, the time taken would be two hours. For the remaining 60 miles at a speed of 60 miles per hour, 1 hour is total time traveled. So, we calculate the average speed as follows:
Average speed = total distance / total time
Average speed = 120 miles / 2 hr + 1 hr
Average speed = 40 mi / hr