Question

A 92-kg water skier floating in a lake is pulled from rest to a speed of 12 m/s in a distance of 25 m. What is the net force exerted on the skier, assuming his acceleration is constant?

Answer 1

Answer:

260 N

Explanation:

The acceleration of the skier is gotten by using an equation of motion:

$v^2=u^2+2as$

where u and v are the initial and final velocities, a is the acceleration and s is the distance.

$a = \dfrac{v^2-u^2}{2s} = \dfrac{12^2-0^2}{2\times25} = 2.88 \text{ m/s}^2$

The force on the slider is then

$F = ma$

$F = 92\times2.88 = 264.96 \text{ N} = 260 \text{ N}$

Answer 2

Answer:

264.96 N.

Explanation:

Force: This can be defined as the product of the mass and the acceleration of a body.

From the question,

F = ma.................. Equation 1

Where m = mass of the water skier, a = acceleration of the water skier.From Newton's equation of motion,

v² = u²+2as.............. Equation 2

Where v and u = final and initial velocity respectively, a = acceleration, s = distance.

Given: v = 12 m/s, u = 0 m/s ( from rest), s = 25 m

Substitute into equation 2

12² = 0²+2(25)(a)

144 = 50a

a = 144/50

a = 2.88 m/s².

Also given: m = 92 kg.

Substitute into equation 1

F = 92(2.88)

F = 264.96 N.