Question

A canoe is drifting left toward a hungry hippo with a velocity of 7\,\dfrac{\text{m}}{\text{s}}7

s
m
​ 7, space, start fraction, m, divided by, s, end fraction. The canoe rider starts paddling frantically, causing the canoe to travel to the right with a constant acceleration of 6 \,\dfrac{\text m}{{\text s}^2}6
s
2

m
​ 6, space, start fraction, m, divided by, s, start superscript, 2, end superscript, end fraction.
after 4\,\text s4s4, space, s, what is the velocity of the canoe?

Answer 1

Answer: 17 m/s

Velocity and acceleration are vector quantities. Let leftwards be defines as negative and rightwards as positive direction.

It is given that canoe is drifting left with a velocity of
`u=-7 m/s`

The canoe rider is moving towards right with a constant acceleration,
`a=6 m/s^2`

we need to find the velocity of canoe after 4 s.

we will use the equation of motion:

`v=u+at`

where, v is the final velocity, u is the initial velocity, a is the acceleration and t is the time.

Insert the values in the above equation:

`\Rightarrow v=-7m/s+6 m/s^2 * 4 s=24m/s-7 m/s=17 m/s`

Hence, velocity of canoe after 4 s would be 17 m/s.