IIT JEE , AIEEE Forum - Physics , Mechanics - inertia

sinjan.j

please see the pic

question is there inside.

astronautameya

the reason is simple.
if he were to stand and jump, then he would only generate a little momentum in the required direction..
on the other hand, when he takes a fast run-up, he already has some momentum, that gets added to his jump and he goes farther.
newton's law says that the body(here, athlete) will move in a given direction with a given velocity till some external force acts on it.(inertia)

more logically, if he jumps from the spot, he has to use the impulse to generate both vertical and horizontal velocities. if he runs, he already has the horizontal velocity, he only needs a vertical impulse to do well.

rate if satisfied

spideyunlimited

in long jump, u want the maximum distance to be covered. in terms of projectile motion, that is the range,,
range depends on the horizontal component of velocity
range = Ux X t where Ux is the horizontal velocity ( which does not change during projectile motion in XY plane)
if horizontal velocity is max. distance covered will be max
therefore they run a certain distance to gain a suitable velocity , and thus inertia, and this inertia propels his jump in the horizontal direction.

nunoxic

Everybody continues in the state of rest or uniform motion until acted upon by an external unbalanced force
By running (or taking what we call as pick up) the athlete aquires something known as INERTIA which causes him to continue with uniform velocity in the straight path
if u consider 2 cases.......one where he takes pick up and runs and second when he directly tries to jump........the distance he will jump in the first case will be much more as he had something which was pushing him forward (or in other words ...... not allowing him to slow down)

(also
s = ut + 1/2 at^2..........when u is non zero its obvious s will be greater.......if u is 0 (case 2)........s will be much less)

Rate If Useful

Ask & Discuss Questions with Community & Experts