An object is moving in a horizontal direction only. the graph shows its velocity vs. time.

Problem 1

Givens

vi = 9 m/s

vf = 4m/s

The time is from 4 to 10 which is 10 - 4 = 6 seconds. Time is never minus.

d = ?

Formula

d = (vf + vi)*t/2

Solve

d = (9 + 4)*6/2

d = 39 m

A <<<<< answer

Problem 2

This one is a seat of your pants kind of problem. Physics teachers are among the best at hiding answers.

Givens

a = ?

vi = x

vf = - 2x

t = 0.41

Formula

a = (vf - vi)/t

Solve

a = (-2x -x) / 0.41

a = -3/0.41 x

a/x = -3/0.41

a/x = - 7.32 The answer is A

Problem 3

Givens

vi = 30 m/s

a =- 1.6 m/s^2

vf = 0

d = ??

vf^2 = vi^2 + 2*a*d

0 = (30 m/s)^2 + 2 * ( -1.62) *d

- 900= - 3.24d

d = 900/3.24

d = 278.8

C answer