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Easy M2 Projectiles Question

A particle of mass 0.5kg is at rest on a horizontal table. It receives a blow of impulse 2.5Ns.

(a) Calculate the speed with which P is moving immediately after the blow

The height of the tablke is 0.9m and the floor is horizontal. In an initial model of the istuation the table is assumed to be smoth.

(b) Calculate the horizontal distance from the egde of the table to the point where P hits the ground.

In a refinement of the model the table is assumed rough. The coefficient of friction between the table and P is 0.2.

(c) Calculate the deacceleration of P.

Given thatP travels 0.4m to the edge of the table,

(d) calculate the time which elapses between P receiving the blow to P hitting the floor.

am having problems with (d), have done (a) to (c)

answers:
(a) 5 ms^-1
(b) 2 1/7 m
(c) 1.96 ms^-2
(d) 0.510s

THANX! :biggrin:

Reply 1

dvs

On the table:
S=ut+0.5at²
0.4=5t-0.98t²
Using the quadratic formula:
t=0.081s until P leaves the table.

Vertical projectile motion:
S=ut+0.5ut² => -0.9=-4.9t² => t=3/7 s when P strikes the ground.

Add them up:
t = 3/7 + 0.081 = 5.10s