1) An electron, starting from rest and moving with a constant acceleration, travels 1.9 cm in 3.8 ms. What is the magnitude of this acceleration is km/s^2.
I got 5 x 10^-4 km/s^2. Is this correct????
2) A tennis ball with a speed of 12.6 m/s is thrown perpendicularly at a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 10 m/s. If the ball is in contact with the wall for 0.014 s, what is the average acceleration of the ball while it is contact with the wall?
I got the answer 1614.29 m/s^2. Is this right???
2007-09-07 08:05:43 · 1 answers · asked by lola 1 in Science & Mathematics ➔ Physics
1. s = at^2/2 ==> a = 2s/(t^2)
a = 0.038/0.0038^2 = 2631.58 m/s^2 = 2.63158 km/s^2
2. The velocity change is 22.6 m/s, and it's done in 0.014 s. Divide 22.6/0.014 = 1614.29 m/s^2. We agree.
2007-09-08 10:58:45 · answer #1 · answered by kirchwey 7 · 0⤊ 0⤋