Question

Sawyer launches his 180 kg raft on the Mississippi River by pushing on it with a force of 75N. How long must Sawyer push on the raft on to accelerate it to a speed 2 m/s?

Answer 1

4.8 seconds

Hope this helps! good luck :)

Answer 2

Answer: 4.8 s

Step-by-step explanation:

We have the following data:

`m=180 kg` the mass of the raft

`F=75 N` the force applied by Sawyer

`V=2 m/s` the raft's final speed

`V_(o)=0 m/s` the raft's initial speed (assuming it starts from rest)

We have to find the time
`t`

Well, according to Newton's second law of motion we have:

`F=m.a` (1)

Where
`a` is the acceleration, which can be expressed as:

`a=(\Delta V)/(\Delta t)=(V-V_(o))/(t-t_(o))` (2)

Substituting (2) in (1):

`F=m(V-V_(o))/(t-t_(o))` (3)

Where
`t_(o)=0`

Isolating
`t` from (3):

`t=(m(V-V_(o)))/(F)` (4)

`t=(180 kg(2 m/s-0 m/s))/(75 N)`

Finally:

`t=4.8 s`