as physics help

[maths maldives]

please someone explain this with formula needed!

The acceleration of free fall on Mars is 3.7 m s–2.
If an object on Mars is launched vertically upwards with an initial speed of 40 m s–1, its
speed after 3.0 s will be

A 11 m s–1
B 29 m s–1
C 36 m s–1
D 51 m s–1

 

[rami-mustang_gt]

U=40
a=3.7
v=?
t=3
use v=u+at
=40+3.7(3)
=51 m/s is it correct ?

 

[maths maldives]

U=40
a=3.7
v=?
t=3
use v=u+at
=40+3.7(3)
=51 m/s is it correct ?

U=40
a=3.7
v=?
t=3
use v=u+at
=40+3.7(3)
=51 m/s is it correct ?

wrong

 

[rami-mustang_gt]

IM SORRY !!!
PROJECTED VERTICALLY UPWARDS SO ACCELERATION IS NEGATIVE !!
a=-3.7
t=3
u=40
v=?
v=u+at
=40-3.7(3)
=29m/s

 

[maths maldives]

Thanks rami-mustang_gt

 

[rami-mustang_gt]

haha, you're welcome !
here i am studying for p2
hope i finish all pastpapers again good luck bro

 

[maths maldives]

Define Hookes law

 

[rami-mustang_gt]

Is when the extension of the load is directly proportional to the load applied on it.

 

[maths maldives]

Isn't it up to the elastic limit

 

[rami-mustang_gt]

Nope, Hookes law applies till limit of proportionality.