## Summersnow8 one year ago How many Newtons of force are required to stop a truck 2250 kg truck going 32.0 km/h in 4.00s? @rajat97

1. shamim

I m not solving ur problem. Because u did not give me medal in ur previous problem

2. rajat97

here, we just need to find the acceleration of the truck(i mean deceleration) and then multiply it with the mass of the truck first we convert everything into SI units the initial speed=u=32km/hr=8.89 m/s the final speed=v=0m/s time=t=4s we can use the kinematical equation v=u+at where a is the acceleration and all the other variables are defined above so from here, you get the acceleration (or the deceleration as we want to stop the truck) of the truck and then we just need to multiply the value of a i.e. acceleration with the mass of the truck i.e. 2250Kg

3. rajat97

i may not be very clear so just feel free to ask anything

4. Summersnow8

how do you find Newtons from all this information?

5. rajat97

by Newtons in the question, they mean 'Force' and we know, force is F=mass x ?

6. Summersnow8

$a = \frac{ V-u }{ t } = \frac{ 0-8,888 }{ 4.00 } = -2.22$ $F = m * a = (2250 * -2.222) = -5000$

7. Summersnow8

*8.888

8. rajat97

Awesome! you are absolutely right!

9. Summersnow8

do i keep the - sign?

10. rajat97

the -ve sign just means that the force is applied in opposite direction to that of the motion of the object which is the truck here

11. Summersnow8

so if i submit an answer, should I submit 5000 or -50000

12. rajat97

you should submit just 5000 as they have asked 'how many newtons' and not the direction of the force i.e. only magnitude

13. Summersnow8

okay thanks for your help

14. rajat97

any time girl!