Apressure is applied to 20 l of water. the volume is observed to decrease to 18.7 l. calculate the applied pressure

Applied  pressure is 1.08 10⁵ Pa

Explanation:

This exercise is a direct application of Boyle's law, which is the application of the state equation for the case of constant temperature.

      PV = nR T

If T is constant, we write the expression for any two points

    Po Vo = p1V1

From the statement the initial pressure is the atmospheric pressure 1.01 10⁵ Pa, so we clear and calculate

      1 Pa = 1 N / m2

     P1 = Po Vo / V1

     P1 = 1.01 10⁵  20/18.7

     P1 = 1.08 10⁵ Pa

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j