Question

I have some equations that I would like checked. Thanxs!

1. An automobile starts from rest and accelerates at 3m/s2 for 4 seconds. How fast is it going after acceleration?


3m/s^2 / 4 = .75 m/s


2. If an automobile travels at 30 km/hr. for 2 hours, how far does it go?

d=(30 km/hr)(2 hr)= 60 km


3. At time = 0 an automobile already traveling at 30 km/hr. accelerates at 3m/s2 for 2 seconds. During these two seconds, how far does it go? (This one I don't understand)

4. An automobile is traveling at 30 km/hr. It accelerates at 3 m/s2 until it has covered 100 meters.. What is its new velocity? (This one I don't understand)

Answer 1

1. Multiply like in number two
2. Right
3. final velocity^2 = initialvelocity^2 + 2*acceleration*(distance traveled)

-- Solve for distance traveled

4. use above equation and solve for final velocity