Physics Forces

Question

a 985kg dragster, starting from rest, attains a speed of 43.6 m/s in 0.82 seconds. what is the acceleration of the dragster?

Answer 1

Use your basic kinematics equation:  V = V₀ + a * T    

V   = velocity

V0 = velocity at time=0

a   = acceleration

T   = Time of acceleration

 

V0 = 0   (Starting from rest means velocity at T=0 is zero)

V = 43.6 m/s

T = 0.82 sec

 

43.6 = 0 + a * 0.82

 

solving for a,  a = 43.6/0.82 = 53.17 m/sec²

 

note:  They are not asking for the Force (= ma), so the mass is not needed to find acceleration)

 

Answer 2

We use the formula

 

v_F = v_i + at

 

where:

v_F = final velocity

v_i = initial velocity

a = acceleration

t = time

m = mass

 

What we know:

v_i = 0 m/s

v_F = 43.6 m/s

t = 0.82 s

m = 985 kg

 

Plug in the known values into the formula to find the acceleration.  Once you have the acceleration, multiply it by the given mass to get your force.