A 425-g model rocket is accelerated upward at 86 m/s^2 by its engine. What is the value of the force exerted by the engine on the rocket? a = 86 m/s^2, m = 425 g,

Question

jamesj · Answer

Newton's Second Law:

Force = Mass x Acceleration
F = ma

anonymous · Answer

i tried that and I got 36 550, but the answers provided are: 41 N [down], 32 N [u], 32 N [down], 37 N [up], and 41 N [up]?... 

btw, what is the general equation for this: y(t) = something involving initial velocity + something involving gravity.

jamesj · Answer

You have to write the mass in kg, so m = 0.425 g.

=====

$$ y(t) = vt - \frac{1}{2}gt^2 $$
where v is the initial velocity

anonymous · Answer

oihhh, omg thank you!

jamesj · Answer

****Correction, m = 0.425 kg,  NOT g.

anonymous · Answer

ohh.. thank you so much!!

anonymous · Answer

so how does that relate to N [direction]?

anonymous · Answer

It asks, "what is the value of the force BY the engine ON the rocket." Therefore, the force we are considering is acting on the rocket. Which direction does the rocket travel? The force must act in the same direction.