Answer:
B ) 1.5 m/s
Explanation:
For the apparent frequency reflected by enemy submarine , the Doppler effect formula is
F = F₀ ( V + v) / (V - v)
F anf F₀ are real and apparent frequency , V and v are velocity of sound and velocity of enemy submarine respectively.
ΔF / F₀ = 
Put ΔF = 200; F₀ = 100000 and V = 1482
200 / 100000 = 
v = 1.5 m s⁻¹ .
The sun gets its power from nuclear fusion. In the suns core.
Answer:
90J
Explanation:
The only time work is being done is when he lifts the box off the ground. Therefore, using the work formula, 2 x 45, you get 90J. Hope this helps someone.
Muscles function only by contracting. This makes it necessary for one end of the muscle to be fixed and the other mobile.
Take the bicep for example.
Its origin is at the shoulder and its two heads connect to the bones of the forearm, the radius and ulna.
Now, had the muscle not been fixed at one end, and contracted, it would pull both our shoulder and forearm together resulting in an ineffective movement. The desired motion is to lift the forearm (proximal and distal movement) which can only be achieved if the bicep is fixed at the shoulder and allowed to move at the forearm.
