Question

a object starts from rest experience a force of 8 N if mass of a object is 4kg then find its a) velocity b) distance travelled after 4sec .​

Answer 1

Answer:

Explanation:Given that,

Mass m=2kg

Initial velocity u=0m/s

Final velocity v=20m/s

Time t=4s

Now, the acceleration is

 v=u+at

a=  

t

v−u

​  

 

a=  

4

20

​  

 

a=5m/s  

2

 

Now, the force is

 F=ma

F=2×5

F=10N

Now, the displacement is

 s=ut+  

2

1

​  

at  

2

 

s=0+  

2

1

​  

×5×16

s=40m

Now, the work done is

 W=F⋅s

W=10×40

W=400J

Now, the power is

 P=  

t

W

​  

 

P=  

2

400

​  

 

P=200watt

Hence, the power is 200 watt  

Answer 2

Answer:

8m/s, 16m

Explanation:

F=8N

m=4kg

F=ma

a=F/m

a=8/4

a=2m/s²

u=0m/s

t=4s

from 1st eq. of motion

v=u+at

v=0+2×4

v=8m/s

from 2 eq of motion

s=ut+1/2×at²

s=0×4+1/2×2×4²

s=16m