# physics-speed

posted by
**Damon**
.

i need help with this one

thanks

A particle starts from rest and is acted on by a net force that does work at a rate that is proportional to the time t. The speed of the particle is proportional to:

a. sq. root t

b. t

c. t^2

d.1/sq. root t

e. 1/t

Work done is proportional to the integral of a constant times t. That means the work done is proportional to t^2. It will equal the final kinetic energy, which is proportional to v^2. Therefore v^2 is proportional to t^2, and v must be proportional to t.