Answer:
(a)
(b) 78 m
Explanation:
Physics' cinematics as rates of change.
Velocity is defined as the rate of change of the displacement. Acceleration is the rate of change of the velocity.
Knowing that
(a) To find the displacement we need to integrate the velocity
(b) The displacement can be found by evaluating the integral
f = 1.32×10^4 N
Explanation:
We can use the work-energy theorem to find the work done by the braking force f:
W = ∆KE + ∆PE
= (KEf - KEi) + (PEf - PEi)
= [(1/2)mvf^2 - (1/2)mvi^2] + (mhf - mghi)
At the bottom of the slope, vf = 0 and hf = 0 and hi = dsin10° (d = braking distance) so work W becomes
W = -[(1/2)mvi^2 + mgdsin10°]
= -m[(1/2)vi^2 + gdsin10°]
= -(2320kg)[(1/2)(13.4m/s)^2 + (9.8 m/s^2)(22.5m)sin10]
= -2.97×10^5 J
Since W = fd, where f is the braking force, we can now solve for f:
f = W/d = (-2.97×10^5 J)/(22.5 m)
= -1.32×10^4 N
Note: the negative sign means that it is a dissipative force.
Answer:
Kinetic energy is given by:
K.E. = 0.5 m v²
Susan has mass, m = 25 kg
Velocity with which Susan moves is, v = 10 m/s
Hannah has mass, m' = 30 kg
Velocity with which Hannah moves is, v' = 8.5 m/s
<u>Kinetic energy of Susan:</u>
0.5 m v² = 0.5 × 25 kg × (10 m/s)² = 1250 J
<u>Kinetic energy of Hannah:</u>
0.5 m v'² = 0.5 × 30 kg × (8.5 m/s)² = 1083.75 J
Susan's kinetic energy is <u>1250 J </u>and Hannah's kinetic energy is <u>1083.75 J</u>.
Since kinetic energy is dependent on mass and square of speed. Thus, speed has a greater effect than mass. As it is evident from the above example. Susan has greater kinetic energy due to higher speed than Hannah.
Answer:
Explanation:
The kinematic equation
gives the final velocity of the object given the initial velocity , the acceleration , and the distance traveled .
For our case, the object is dropped; therefore,
I.e. the initial velocity is zero. The acceleration due to gravity is
,
and the distance traveled is .
Putting the values into the equation we get:
The final velocity of the object is 44.27 m/s.