3s
Explanation:
Given parameters:
Mass of car = 1000kg
Force applied = 8000N
speed = 24m/s
Unknown:
time taken for the car to stop = ?
Solution:
According to newton's second law of motion; "the force on a body is the product of its mass and acceleration".
Force = mass x acceleration
let us find the acceleration of the car;
a =
=
= 8m/s²
since the car is accelerating at a rate of 8m/s², when the brakes are applied, it will start decelerating at the constant rate, - 8m/s²
Applying the appropriate equation of motion;
V = U + at
V is the final velocity
U is the initial velocity
a is the acceleration
t is the time taken
final velocity = 0
0 = U + at
-U = at
-24 = -8t
t = 3s
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There are no true statements on that list.
Answer:
The collision is not elastic. The system increases his kinetic energy m*v₀² times.
Explanation:
Assuming no external forces acting during the collision, total momentum must be conserved.
Considering the information provided, we can write the momentum conservation equation as follows:
m*v₀ = -m*v₀ + 2*m*vf
Solving for vf, we arrive to this somehow surprising result:
vf = v₀ (in the same direction that m was moving before the collision).
In order to determine if the collision was elastic, or not, we need to calculate the kinetic energy of the system before and after the collision:
K₀ = 1/2*m*v₀²
Kf = 1/2*m*v₀² (due to the object of mass m, as the kinetic energy is always positive) + 1/2 (2m) * v₀²
⇒Kf = 1/2*m*v₀² + 1/2 (2m) * v₀² = 3/2*m*v₀²
ΔK = Kf - K₀ = 3/2*m*v₀² - 1/2*m*v₀² = m*v₀²
As there is a net difference between the final and initial kinetic energies, and the total kinetic energy must be conserved in an elastic collision (by definition) we conclude that the collision is not elastic, and the change in the kinetic energy of the system is equal to m*v₀².
Answer:
Explanation:
a ) Let let the frictional force needed be F
Work done by frictional force = kinetic energy of car
F x 107 = 1/2 x 1400 x 35²
F = 8014 N
b )
maximum possible static friction
= μ mg
where μ is coefficient of static friction
= .5 x 1400 x 9.8
= 6860 N
c )
work done by friction for μ = .4
= .4 x 1400 x 9.8 x 107
= 587216 J
Initial Kinetic energy
= .5 x 1400 x 35 x 35
= 857500 J
Kinetic energy at the at of collision
= 857500 - 587216
= 270284 J
So , if v be the velocity at the time of collision
1/2 mv² = 270284
v = 19.65 m /s
d ) centripetal force required
= mv₀² / d which will be provided by frictional force
= (1400 x 35 x 35) / 107
= 16028 N
Maximum frictional force possible
= μmg
= .5 x 1400 x 9.8
= 6860 N
So this is not possible.
Answer:
V' = 4.56Km/s
Explanation:
We can use the formula of Orbital Speed, who say,

The relative velocity is given by,

We need to find the relation between the two speeds,



Substituting,

