## anonymous one year ago acceleration and velocity

1. anonymous

A train travels at a velocity of +50 m/s. It takes 80 s to slow down to 5 m/s with constant acceleration. What was its acceleration? A. -0.064 m/s2 B. -0.56 m/s2 C. -8.0 m/s2 D. -10.0 m/s2 On Earth a rock is dropped and falls 4.9 meters just before it hits the ground. How much time did the rock take to fall this distance? A. 0.5 s B. 1.0 s C. 1.2 s D. 2.45 s A girl throws a tennis ball upward with an initial velocity of 4 m/s. What is the maximum displacement of the ball? A. 0.2 m up B. 0.4 m up C. 0.8 m up D. 1.6 m up A car traveling at +30 m/s brakes to exit the highway with an average acceleration of -3 m/s2. About how long is it before the car slows to +5 m/s? A. 5 s B. 8 s C. 10 s D. 18 s A child throws a penny straight down into a wishing well. The penny's initial speed is 2 m/s. If the penny takes 3 seconds to hit the water, how deep is the well? A. 20 m down B. 46 m down C. 50 m down D. 94 m down A spaceship starting from a resting position accelerates at a constant rate of 9.8 meters per second per second. How far will the spaceship travel if its final speed is 1 percent the speed of light (300,000,000 m/s)? A. 3.1 × 106 m B. 2.94 × 108 m C. 7.8 × 1010 m D. 4.6 × 1013 m A model rocket is shot straight upward with an initial velocity of 32 m/s. Its upward acceleration is a constant 6 m/s2. When the fuel is used up at a height of 75 m, what is its velocity? A. 30 m/s up B. 32 m/s up C. 38 m/s up D. 44 m/s up A car starts from a resting position and accelerates at a constant rate of 6 meters per second per second. What is the car's speed after it has traveled 250 meters? A. 41.7 m/s B. 54.8 m/s C. 127.3 m/s D. 1500 m/s If a bicyclist starts from a resting position and reaches a speed of 10 meters per second in 40 seconds, what was his acceleration during this time? Assume he accelerated in a constant way. A. 0.25 m/s2 B. 0.50 m/s2 C. 0.75 m/s2 D. 1.00 m/s2 On Mars a rock falls an unknown vertical distance from a resting position and lands in a crater. If it takes the rock 2.5 seconds to fall, how high is the cliff the rock fell from? Mars' surface gravity is 3.8 m/s2. A. 9.5 m B. 11.9 m C. 15.2 m D. 23.8 m

2. zephyr141

use these equations $a=\frac{ v-v_0 }{ t-t_0 }$$d=v_ot+\frac{ 1 }{ 2 }at$$v^2=v_0^2+2ad$$v=v_0+at$$d=\frac{ v_0-v }{ 2 }t$you should be able to solve for all of them with these equations. i think. also you have to look up mar's acceleration due to gravity.

3. anonymous

(3.8 m/s2)?

4. anonymous

thank u

5. anonymous

didn't know the equations to use, do to being absent.

6. zephyr141

yeah most of these questions can be answered just by using the first kinematic equation. not the equation for acceleration.

7. zephyr141

good luck.

8. anonymous

thanks again, im closing the question if i have a problem find an answer ill just ask u

9. zephyr141

criiipes. ok here's a correction for one of the equations. i just realized i forgot a 2nd power on one of the variables. $d=v_0t+\frac{ 1 }{2 }at^2$that's the correct equation.