Speed, Velocity & Acceleration 9/27/10. Position vs Distance. Position is an objects location compared with where it started, including direction Distance is a length without regard to direction
If there are turns, the position might be different from the distance traveled
Speed is the slope of the position vs time graphPosition vs time graph
50 km = 2 hr
Δd = df – di = 10km – 0km = 10km
Δt tf – ti 0.5 hr – 0 hr 0.5 hr
50 km = 2 hr
Δd = df – di = 15km – 10km = 5 km
Δt tf – ti 1 hr – 0.5 hr 0.5 hr
Acceleration = Change in velocity
Change in time (Δt)
change in speed10 km/h
Acceleration = time interval = 1s = 10 km/h-s
Two time entries in answer; first for unit of speed (km/h), second for time interval in which speed is changing (-s)
The 3rd law says the ball exerts a force an equal and opposite force on you.
Your force makes the ball accelerate in one direction and the reaction makes you accelerate in the opposite direction.The motion of objects
If you throw a heavier ball away fast, you backward acceleration is greater than if you throw a lighter ball.
The backward acceleration is called recoil.What happens if you throw a heavier ball?
Before you throw the ball, your and the ball’s momentum is zero. In order for conservation of momentum to be true, after you throw the ball the total momentum must be zero.
(1 kg)(-20 m/s) + (40kg)(0.5m/s) = 0
c. What is the change in momentum?