Some substances look alike and the density can help you determine which is which. It also helps to tell which is heavier than the other.
Answer:
A) 3.13 m/s
B) 5.34 N
C) W = 26.9 J
Explanation:
We are told that the position as a function of time is given by;
x(t) = αt² + βt³
Where;
α = 0.210 m/s² and β = 2.04×10^(−2) m/s³ = 0.0204 m/s³
Thus;
x(t) = 0.21t² + 0.0204t³
A) Velocity is gotten from the derivative of the displacement.
Thus;
v(t) = x'(t) = 2(0.21t) + 3(0.0204t²)
v(t) = 0.42t + 0.0612t²
v(4.5) = 0.42(4.5) + 0.0612(4.5)²
v(4.5) = 3.1293 m/s ≈ 3.13 m/s
B) acceleration is gotten from the derivative of the velocity
a(t) = v'(t) = 0.42 + 2(0.0612t)
a(4.5) = 0.42 + 2(0.0612 × 4.5)
a(4.5) = 0.9708 m/s²
Force = ma = 5.5 × 0.9708
F = 5.3394 N ≈ 5.34 N
C) Since no friction, work done is kinetic energy.
Thus;
W = ½mv²
W = ½ × 5.5 × 3.1293²
W = 26.9 J
Answer:
Energy is essentially work done by an object or on object.
From,
W = Fd
It's directly proportional to mass.
from,
K. E = 1/2mv²
Energy is directly proportional to mass.
P. E = mgh
Energy is directly proportional to mass.
H = mc∆T
Energy is directly proportional to mass.
Thus increasing mass will increase the energy also imparted on another object since all the above eqns show that relationship.
And for 2 moving bodies
K.Ei = K.Ef(energy conservation)
m1u²1 + m2u²2 = m1v²1 + m2v²2
The relationship is the same that the greater mass the greater the impact.
The car has an initial velocity 
of 23 m/s and a final velocity 
of 0 m/s. Recall that for constant acceleration,
The car stops in 7 s, so the acceleration is
both it velocity and acceleration is zero.
