What is the Mass of a Block of Ice Given a Constant Force and Displacement?

[MissKaylaPaige]

Homework Statement

A Constant force of 75 N is applied horizontally to a block of ice on a horizontal plane. Friction is negligible. The block moves 12 m in the first 3 seconds. Find Mass in kg of block.

Homework Equations

F=m*a

m=F/a

The Attempt at a Solution

Having trouble finding acceleration. I took 12m/3s to find the velocity, then velocity over time to give acceleration. I came up with 1.3 but this appeared to be incorrect. Help with the proper finding of acceleration would be great.

 

[pinkyjoshi65]

is the answer 28.12 Kg?

 

[hage567]

Homework Statement

A Constant force of 75 N is applied horizontally to a block of ice on a horizontal plane. Friction is negligible. The block moves 12 m in the first 3 seconds. Find Mass in kg of block.

Homework Equations

F=m*a

m=F/a

The Attempt at a Solution

Having trouble finding acceleration. I took 12m/3s to find the velocity, then velocity over time to give acceleration. I came up with 1.3 but this appeared to be incorrect. Help with the proper finding of acceleration would be great.

If the block starts from rest, the initial velocity is zero. So if you know the distance, time and initial velocity, which kinematic equation will give you acceleration?

 

[MissKaylaPaige]

Ahh yes it is, could you tell me what you did to get the acceleration?

 

[MissKaylaPaige]

Ahhh I didn't even look at the kinematic equations. I will do that.

 

[BatmanACC]

If it starts from rest you know:

- V1=0
- V2=?
- Displacement=12m
- Time=3s

To get V2 we use the equation that relates all our known variables. This equation is; Delta D={(v1+v2)/2}* Delta Time

After you find V2 use the equation A= (V2-V1)/Delta Time to find acceleration. From there plug A into Fnet=ma and find mass.

 

[MissKaylaPaige]

Awesome, that all works, thanks :)