Physics Newtons laws

Question

A 873-kg dragster, starting from rest, attains a speed of 26.3 m/s in 0.59 s.

a. Find the average acceleration of the dragster.

b. What is the magnitude of the average net force on the dragster during this time?

c. What horizontal force does the seat exert on the driver if the driver has a mass of 68 kg?

Answer 1

a) Average acceleration is change in velocity over change in time, <a> = Δv/Δt = (26.3 - 0)/ 0.59 = 44.6 m/s².

b) Average force is mass times acceleration, <F> = M <a> = (873)(44.6) = 38,900 N (to 3 sig figs).

c) Horizontal force of the seat, which has this same acceleration, is F_x = m <a> = 3,030 N.

Answer 2

(a)

a = (v₂ - v₁)/t

v₁ = 0

v₂ = 26.3 m/s

t = 0.59 s

Plug in these numbers and get acceleration in units of m/s².

(b)

F = Ma

M = 873 kg

Use the result from part (a) for the acceleration. Plug in the numbers and get F in units of newtons.

(c)

F = ma

Use the same acceleration, but use the mass of the driver.

m = 68 kg

Plug in the numbers and get F in units of newtons.