Answer:
a. 5 Hertz
b. 35 rotations
Explanation:
a. Frequency is given by
where
is the period, in seconds. Given that
, the frequency of this object's rotation is:

b. Since one rotation, or period, is completed in 0.2 seconds, divide the amount of time (7 seconds) by the time it takes to complete one revolution (0.2 seconds):

Answer:

Explanation:
As the 2 force directions are perpendicular (North vs West), we can calculate the magnitude of the net force using the following equation

Assuming negligible friction, from here we can calculate the acceleration in accordance to Newton's 2nd law of motion

E = mc²
E = 0.235 kg · (3×10⁸ m/s)² = 0.235 · 9×10¹⁶ kg·m/s²
E = 2.115×10¹⁶ J
The answer is d) 2.12×10¹⁶ J