Interesting question. Please answer and be blessed?

I am really stuck on this question and i just want to know how to get to the answer. I would really appreciate an explanation and sighting of the equation used. THis is a GCSE physics question. Thanx and like i said if u help me out ur blessed cus i'm really stuck on physics and my exams next week. Now heres the question:



A 2 kg object changes from travelling at 10 m/s to 5 m/s in 2 s. What force was needed to do this?

A)0.2 N

B)5 N

C)20 NInteresting question. Please answer and be blessed?
b



The acceleration is the change of velocity over time ( or the rate of change of velocity) the change is 5 and this occurs of 2 seconds. ( 5/2)=a



Then use f=ma



f= 2( mass) * (5/2)

f=5Interesting question. Please answer and be blessed?
Change in momentum = ( 2)*(10 - 5) = 10 kg - m = impulse = F x time = 2 * F

10 = 2 F

F= 5 N..................ans



B)5 N..........ans
from Newton's second law you know that a=F/m

what is acceleration equal to

a=(v-vo)/t

substitude this into the last equation and you get

(v-vo)/t=F/m

F=m*(v-vo)/t

but in the numbers in and you get

F=5 N ( you can change the v and vo position in this equation so that you do not have a minus sign)
friend.Let us use newton's 2nd law of motion, F = MA.we know that acceleration is = (final velocity -initial velocity)/2.so acceleration is (5 - 10)/2 = -5/2.so force required is 2 * -5/2 so the answer is 5 newtons in the opposite direction