A sonar emits a sound signal of frequency 40000Hz, towards the bottom of the sea. This signal is reflected on the body of a submarine after a delay of 0.3 seconds.
Given: Speed of sound in water is 1500 m/s.

Calculate the period of this wave.

0.000025s

Explanation:

Period it’s. : T(s)= 1/f(Hz)=1/40000Hz=0.000025s

if the forces acting on an object are unbalanced, the object will accelerate in the direction of the net force on the object.

explanation:

this is best explained by having an understanding of newton's second law, which states that f=ma. you see, when the forces are unbalanced, net force (sum of all forces) is not zero. therefore making it necessary for the object to have an acceleration in the direction of the net force.

f=ma newton

f=100x2.5=250n