Answer: 2045
Explanation:
Given
We had sent a radio signal to advance civilization in 2006 which is 39 light-years away i.e. time taken by light to reach reticuli star system is 39 years.
So, it will arrive the destination in the year 
Answer:
F = 0.0034 N
Explanation:
Given:

The angle between B and wire = 90 - 57 = 33 degrees
Using formula:

An example of an energy conversion that produces an unwanted form of energy is mixing acids with water.
Answer:
3 kg
Explanation:
Momentum before = momentum after
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
After jumping on the skateboard, the student and the skateboard have the same velocity, so v₁ = v₂.
m₁u₁ + m₂u₂ = (m₁ + m₂) v
(47.4 kg) (4.2 m/s) + m (0 m/s) = (47.4 kg + m) (3.95 m/s)
m = 3 kg