A 28-kg beginning roller skater is standing in front of a wall. By pushing against the wall, she is propelled backward with a velocity of -1.2 m/s. While pushing, her hands are in contact with the wall for 0.80 s. Ignoring frictional effects, find the magnitude and direction of the impulse acting on the skater.

Respuesta :

Answer:

33.6 Ns backward.

Explanation:

Impulse: This can be defined as the product of force and time. The S.I unit of impulse is Ns.

From Newton's second law of motion,

Impulse = change in momentum

I = mΔv................................. Equation 1

Where I = impulse, m = mass of the skater, Δv = change in velocity = final velocity - initial velocity.

Given: m = 28 kg, t = 0.8 s, Δv = -1.2-0 = -1.2 m/s (Note: the initial velocity of the skater = 0 m/s)

Substituting into equation 1

I = 28(-1.2)

I = -33.6 Ns

Thus the impulse = 33.6 Ns backward.

Impulse can be defined as the change in momentum. The impulse is 33.6 Ns backward as the sign on impulse is negative.

 

Impulse:

It can be defined as the product of force and time or a change in momentum. The S.I unit of impulse is Ns.  

[tex]I = m\Delta v[/tex]

Where,

[tex]I[/tex]= impulse,

[tex]m[/tex] = mass of the skater = 28 kg

[tex]\Delta v[/tex] = change in velocity = [tex]-1.2-0 =\bold { -1.2 \ m/s }[/tex]

 

Put the values in the equation,

[tex]I = 28 (-1.2)\\\\I = -33.6 \rm \ Ns[/tex]

Therefore, the impulse is 33.6 Ns backward as the sign on impulse is negative.

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