I believe the answer is Microwaves (just to clarify, not the oven). They're widely used for communications.<span />
Answer: 0.5 m/s
Explanation:
Given
Speed of the sled, v = 0.55 m/s
Total mass, m = 96.5 kg
Mass of the rock, m1 = 0.3 kg
Speed of the rock, v1 = 17.5 m/s
To solve this, we would use the law of conservation of momentum
Momentum before throwing the rock: m*V = 96.5 kg * 0.550 m/s = 53.08 Ns
When the man throws the rock forward
rock:
m1 = 0.300 kg
V1 = 17.5 m/s, in the same direction of the sled with the man
m2 = 96.5 kg - 0.300 kg = 96.2 kg
v2 = ?
Law of conservation of momentum states that the momentum is equal before and after the throw.
momentum before throw = momentum after throw
53.08 = 0.300 * 17.5 + 96.2 * v2
53.08 = 5.25 + 96.2 * v2
v2 = [53.08 - 5.25 ] / 96.2
v2 = 47.83 / 96.2
v2 = 0.497 ~= 0.50 m/s
Answer: here are 1,000m in a km, so 200km is 200,000m
200,000m/10m/s = 20,000s
Explanation:
The frequency of a wave is a measure of the number of waves that passes through a point per unit of time. It has SI units of s^-1. It is also equivalent to Hertz (Hz). We calculate the frequency of the wave described as follows:
Frequency = 5 waves / 2 s = 2.5 / s or 2.5 Hz
