Camels have broad feet. Why?

theloveforphysics

Camels have broad feet so that they can walk on sand. As the area of their feet is more, the pressure due to their weight on the sand is less. So they can walk easily without sinking their feet on the sand.

Flash of lightning is seen before the sound of thunder. Why

   Both sound and light energy are released at the same time. In air the speed of light is 300000000 m/s and speed of sound is 340 m/s. Hence the light reaches the observer instantly and sound after some time.

    For example, if an electric discharge  between the clouds takes place at a distance of 1km from the observer then lightning flash is seen instantly but sound of thunder will be heard after about 3 seconds.

It is advantageous to run before taking a long jump. Why?

When we run, our body gains inertia of motion due to which it wants to be in motion continuously. When we take long jump our body has the tendency to be thrown forward more.

NEWTON'S SECOND LAW OF MOTION

The Second law states that the rate of change of momentum is directly proportional to the applied force and the change takes place in the direction of the force applied.

If u= initial velocity,
v=final velocity,
t= time taken to change the velocity from u to v,

Then
Initial momentum = mu
Final  momentum=mv

So change in momentum = mv-mu =m(v-u)
Hence the rate of change of momentum = m(v-u)/t

Therefore F= m(v-u)/t
  F=ma.