Answer:
7.5s
1.6666 repeating or 1.67 m/s²
Step-by-step explanation:
the equation you have to use is Vfinal=Vstart+acceleration•time
(I'm gonna simplify to Vf=Vs+at)
so you gotta rework it for the two equations
for the first equation you need time so take Vf=Vs+at and subtract Vs on both sides to get Vf–Vs=at
then divide acceleration on both sides to get t=(Vf–Vs)/a
for the second problem equation need the equation a=(Vf–Vs)/t (just divide time on both sides instead of acceleration)
so you the plug in
(I don't put the units in to the problem unless needed)
1. t=(Vf–Vs)/a to t=(0–30)/-4.0
t= -30/-4.0
t=7.5 seconds
2. a=(Vf–Vs)/t to a=(10–0)/6.0
a= 10/6.0
a= 1.67m/s²
(I'm assuming the that for number two they started at rest so it would be 0m/s for velocity start)
Answer:
Carly didn't make a mistake
Step-by-step explanation:
24 / (4 x 2 - 5)
PEMDAS
P: Parenthesis = (4 x 2 - 5)
E: Exponents: None
M: Multiplication = (4 x 2 - 5) = (8 - 5)
D: Division = Not yet, because the Parenthesis is not done.
A: Adding = None
S: Subtracting = (8 - 5) = 3
Divide = 24/3 = 8
#54 is wrong is A is says full to shaded
1) Determine the horizontal force, Fx, exerted by the block on Usain
cos(20°) = Fx / F => Fx = F*cos(20) = 1700N*cos(20) = 1597.48 N
2) Determine the Impulse of that force on Usain.
I = F*t = 1597.48N * 0.32s = 511.19 N*s
3) Determine change in momentum of Usain, Δp
Δp = I = 511.19 N*s
4) Find change if velocity
Δp = Δ(mV) = mΔV => ΔV = Δp / m = 511.19 N*s / 86 kg = 5.94 m/s
Given the Usain started from rest, the velocity is ΔV - 0 = 5.94 m/s
Answer: 5.94 m/s