An object started to move from its starting point with the initial velocity of 3.6 m/s to the right and constant decelerating at 1.2 m/s. What is the velocity and displacement when time is 1 sec? 2 secs? 3 secs? 4 secs? 5 secs? 6 secs?
1 Answer
Oct 11, 2015
After one second:
Explanation:
The displacement calculation is different from the
v_"final" = v_"initial" + "acceleration" xx "time"
"diplacement" = v_"initial" xx "time" + 1/2 xx "acceleration" xx "time"^2
Notice that the acceleration is opposite direction to the initial velocity, so we show it as negative.
So:
d_"1 sec" = 3.6"m"/cancel("s") xx 1cancel("s") + 1/2 xx (-1.2"m"/cancel("s"^2) xx 1^2cancel("s"^2))
= "3.6 m" + (-"0.6 m")
= "3.0 m" -> after 1 second
and:
d_"2 sec" = 3.6 "m"/cancel("s") xx 2 cancel("s") + 1/2 xx ( -1.2"m"/cancel("s"^2) xx 2^2cancel("s"^2))
= "7.2 m" + ( -"2.4 m")
= "4.8 m" -> after 2 seconds
