Answer:
4.2 m/s
Explanation:
The velocity-time graph is piecewise linear. The acceleration in each of the three segments of the graph is uniform. The instant lies between and t = 6.0s 100 s, so the acceleration must be calculated using the slope of the middle segment.
a =
(9.6 -2.4)m/s
------------------
(10.0 -6.0)s
= 1.8 m/s2
The instantaneous velocity is to be found after the object accelerates over an interval T = (7.0 - 6.0) s = 1.0 s, starting from a velocity of 2.4 m/s,
So the velocity at t = 7.0 s is
v = u + aT = 2.4 m/s + (1.8 m/s2)(1.0 s) = 4.2 m/s
