Question

I need help with this word problem please ​

Answer 1

-60 m/s²

Explanation:

We are not given the velocity of the plane at landing but we are given velocities at two time periods

V₅, the velocity of the plane 5 seconds after landing is 110 m/s

Plugging this into the velocity equation we get

`\bold{v_5 = a.5 + v_0 = 5a + v_0}` (1)

Similarly

`\bold{v_(15) = a.15 + v_0 = 15a + v_0}` (2)

Subtract (1) from
`v_(15) - v_5 = (15a + v_0) - (5a + v_0) = (15a-5a) + (v_0-v_0) = 10a`

Therefore
`a = (v_(15) - v_5)/(10)`

Given
`v_(15)= 50 m/s \textrm{ and } v_5 = 110m/s`

this evaluates to

`a = (50-110)/10 =` -60 m/s²

The negative value is because the plane is actually decelerating which is a negative number