An average person can reach a maximum height of about 60 cm when jumping straigh

Question

An average person can reach a maximum height of about 60 cm when jumping straight up from a crouched position. During the jump itself, the person's body from the knees up typically rises a distance of around 50 cm. To keep the calculations simple and yet get a reasonable result, assume that the entire body rises this much during the jump.

With what initial speed does the person leave the ground to reach a height of 60 cm?

In terms of this jumper's weight W , what force does the ground exert on him or her during the jump?

Explanation / Answer

Here,

height , h = 60 cm = 0.60 m

distance , d = 50 cm = 0.50 m

let the initial speed the person is v

v = sqrt(2 * g * h)

v = sqrt(2 * 9.8 * 0.60)

v = 3.43 m/s

the initial speed of person must be 3.43 m/s

---------------------

let the acceleration of jumper is a

Using third equation of motion

v^2 - u^2 = 2 * a * d

3.43^2 = 2 * a * 0.50

a = 11.76 m/s^2

Now , force exerted on ground = m * (g + a)

force exerted on ground = m * (11.76 + 9.8)/(m * 9.8) W

force exerted on ground = 2.2 W

the force exerted on the ground is 2.2 W

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.