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
Average velocity is a vector unit (i.e. includes magnitude <em>and </em>direction) calculated by working out distance ÷ time:
80 metres ÷ 20 seconds = 4 metres/seconds (m/s)
Therefore, your final answer is C. 4 m/s south.
Explanation:
When you run, your body has a kinetic energy and when you fall while running, the friction between the carpet and your foot, transforms the kinetic energy into thermal energy or heat energy. This can even cause, real burn if the skin were too hot.
Answer:
It has potential energy
PE = 15450.75 J
Explanation:
we know its potential energy because the carriage is not moving, although it can
PE = mgh
in this case, m is 75, h is 21, and g is always 9.81
plug these in: PE = (75) (21) (9.81)
your answer: PE = 15450.75 J
