What is the displacement and velocity of a falling object after 1.0 s?

[Lana Elcic]

Homework Statement

A rock is thrown straight down with an initial velocity of 10.5 m/s from the Verrazano Narrows Bridge in New York City. The roadway of this bridge is 70 m above water. Take upwards to be the positive direction.

Calculate the displacement and velocity at a time of 1.0 s.

The attempt at a solution
-5.6

 

[C. Lee]

Homework Statement

A rock is thrown straight down with an initial velocity of 10.5 m/s from the Verrazano Narrows Bridge in New York City. The roadway of this bridge is 70 m above water. Take upwards to be the positive direction.

Calculate the displacement and velocity at a time of 1.0 s.

The attempt at a solution
-5.6

So what is your question?

Can you give some more details on how you ended up with that answer?

 

[Lana Elcic]

I've figured out the displacement by (10.5)(1)+(1/2)(9.8)(1.0)^2=-15.4
I don't know how to find velocity though.

So what is your question?

Can you give some more details on how you ended up with that answer?

 

[C. Lee]

I've figured out the displacement by (10.5)(1)+(1/2)(9.8)(1.0)^2=-15.4
I don't know how to find velocity though.

Alright.

So, you have used the gravitational acceleration 9.8m/s^2 to calculate the displacement.

What is the definition of acceleration?

 

[Lana Elcic]

rate of change of velocity

Alright.

So, you have used the gravitational acceleration 9.8m/s^2 to calculate the displacement.

What is the definition of acceleration?

 

[C. Lee]

rate of change of velocity

Right. So the acceleration is constant, and you are given with initial velocity. You can now calculate the velocity at t = 1.0 s.

 

[Lana Elcic]

Awesome! Thanks a lot

Right. So the acceleration is constant, and you are given with initial velocity. You can now calculate the velocity at t = 1.0 s.