Answer:
a) 1m/s
b) -1m/s
Explanation:
So the ball starts rolling up the hill with a speed of 2m/s (v0=2m/s) and it decelerates at a constant rate of 0.5 m/s2 (a = -0.5 m/s², minus because it decelerates).
Now, the equation for calculating velocity is:
v = v0 + a • t, where t represents time
So, ball's velocity after 2 seconds is:
v = 2m/s + (-0.5m/s²• 2s)
v = 2m/s + (-1m/s)
v = 1m/s
We use the same formula for finding ball's velocity after 6 seconds:
v = v0 + a • t
v = 2m/s + (-0.5m/s² • 6s)
v = 2m/s + (-3m/s)
v = -1m/s
Of course, velocity can't be negative, this only means that the ball moves in 1m/s velocity, only in opposite direction (downhill).