acceleration: is this accelerating?

[emma402]

Which of the following objects is accelerating:

1. A motorcycle rounds a curve without changing speed.
2. A helicopter ascending straight upward without speeding up for slowing down.
3. A person jogging straight south at a constant speed.
4. A bus starts moving after waiting for a stoplight, traveling in a straight line.
5. A car speeds up while driving east along a level road.
6. A car drives at a constant 45mph as it goes over the top of a hill

What I think as solutions....(correct me please)

1. yes 4.yes
2. no 5.yes
3. no 6.yes

[kuruman]

Are your answers correct?

1. yes 4.yes
2. yes 5.yes
3. yes 6.yes

For future reference: Please explain your reasoning for each of your answers. That way, if we see anything wrong with it, we can point it out.

[emma402]

i put no for 2&3 b.c there are not changing speed or direction

[kuruman]

i put no for 2&3 b.c there are not changing speed or direction
And you are correct in thinking so.

[emma402]

great, thanks!