Answer:
58.54 kg
23.247 m
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration
m = Mass
a) Equation of motion
[tex]s=ut+\frac{1}{2}at^2\\\Rightarrow 12.5=0\times 4.5+\frac{1}{2}\times a\times 4.5^2\\\Rightarrow a=\frac{12.5\times 2}{4.5^2}\\\Rightarrow a=1.23\ m/s^2[/tex]
Force
F = ma
[tex]m=\frac{F}{a}\\\Rightarrow m=\frac{72}{1.23}\\\Rightarrow m=58.54\ kg[/tex]
Mass of block is 58.54 kg
b)
[tex]v=u+at\\\Rightarrow v=0+1.23\times 4.5\\\Rightarrow v=5.535\ m/s[/tex]
If this velocity is constant then
Distance = Speed × Time
[tex]\text{Distance}=5.535\times 4.2\\\Rightarrow \text{Distance}=23.247\ m[/tex]
Distance the block move in the next 4.20 s is 23.247 m
