Question

Turner’s treadmill starts with a velocity of
−2.7 m/s and speeds up at regular intervals
during a half-hour workout.After 33 min, the
treadmill has a velocity of −7.1 m/s.
What is the average acceleration of the
treadmill during this period?
Answer in units of m/s2

Answer 1

It starts with a negative velocity?

Answer 2

Yes

Answer 3

You can't have a negative velocity.

Answer 4

If you're moving, then your velocity is always positive.

Answer 5

The lowest your velocity can ever be if measured from an inertial referent is 0

Answer 6

velocity is a vector so it can be negative or positive

Answer 7

Not true. Depends on your inertial reference frame and axis of choice...

Answer 8

Okay, the paper says it has negative velocity.

Answer 9

It only makes sense geometrically, not physically

Answer 10

Can anybody help me on this?

Answer 11

in any case the answer is:
-(7.1-2.1)/(33*60)

Answer 12

just take the difference in speed. then divide it by the ammount of passed seconds.

Answer 13

use the newtons equations for constant acceleration
v = u + a t
-7.1 = -2.7 + a * 33 * 60

- sove for a

Answer 14

i.e. if you have a speed, [m/s] and you have a time interval [min]=[60*s]

and you need an answer in [m/s^2]

Answer 15

Does anyone have the answer?