Answer
(a) The mass of the block is 90.9 kg.
(b) The block moves 22.0 meters in the next 5.00 seconds.
Work Step by Step
(a) We can find the acceleration of the block.
$x = \frac{1}{2}at^2$
$a = \frac{2x}{t^2} = \frac{(2)(11.0~m)}{(5.00~s)^2}$
$a = 0.880~m/s^2$
We can find the mass of the block.
$F = ma$
$m = \frac{F}{a} = \frac{80.0~N}{0.880~m/s^2}$
$m = 90.9~kg$
The mass of the block is 90.9 kg.
(b) We can find the speed at t = 5.00 s.
$v = at = (0.880~m/s^2)(5.00~s) = 4.40~m/s$
We can find the distance $x$ the block moves in the next 5.00 seconds.
$x = vt = (4.40~m/s)(5.00~s) = 22.0~m$
The block moves 22.0 meters in the next 5.00 seconds.
