Coal power, using fossil fuels.
Answer: I am pretty sure that you should pick radio waves.
Explanation: The scientist should use radio waves. I think this because you can use the radio waves to analyze the signals from outer space. This will work much better than anything there, to analyze it the best possible.
The best I could do.
Answer: 6700m/s^2 E
Explanation:
Given the following :
Velocity of ball before being hit by a racquet = initial velocity(u) = 55m/s W
Velocity of the ball after being hit = final Velocity (v) = 45m/s E
Time of contact between ball and racquet (t) = 1.5 × 10^-2
The acceleration of a body is the change in Velocity of a body with time. It given by:
Acceleration (a) = [final Velocity(v) - initial velocity(u)] / time(t)
The westward direction is towards the left and thus Velocity takes a negative value, similarly, if it's towards the right, Velocity takes a positive value.
Therefore,
a = [45 - (-55)] / 1.5×10^-2
a = [45 + 55] / 0.015
a = 100 / 0.015
a = 6666.6666 m/s^2
a = 6700m/s^2 E
Since the value of acceleration is positive, the direction is towards the East (acceleration is in the direction of the ball's final Velocity).