Answer:
Time taken for car to stop = 0.89 seconds (Approx.)
Explanation:
Given:
Mass of car = 1100 kg
Speed of car = 15 m/s
Impact force = 185,000 N
Find:
Time taken for car to stop
Computation:
Change in momentum of car = M(v) - M(u)
Change in momentum of car = 1100(0) - 1100(15)
Change in momentum of car = -16,500
Time taken for car to stop = I Change in momentum of car I / Impact force
Time taken for car to stop = I-16,500I / 185,000
Time taken for car to stop = 0.89 seconds (Approx.)
Answer:
In an elastic collision, the total kinetic energy is conserved, while in an inelastic collision, it is not
Explanation:
Let's define the two types of collision:
- Elastic collision: an elastic collision is a collision in which:
1) the total momentum of the system is conserved
2) the total kinetic energy of the system is conserved
Typically, elastic collisions occur when there are no frictional forces acting on the objects in the system, so that no kinetic energy is lost into thermal energy. An example of elastic collision is the collision between biliard balls.
- Inelastic collision: an inelastic collision is a collision in which:
1 ) the total momentum of the system is conserved
2) the total kinetic energy of the system is NOT conserved
In an elastic collision, part of the total kinetic energy is lost (=converted into thermal energy) due to the presence of frictional forces. An example of inelastic collision is the accident between two cars, in which part of the energy is converted into heat.
Solve for acceleration:
<em>a</em> = (21.4 m/s - 33.8 m/s) / (4.7 s)
<em>a</em> ≈ -2.6 m/s²
Solve for force:
<em>F</em> = (1400 kg) <em>a</em> ≈ -3700 N
The minus sign tells you the force points in the opposite direction of the car's motion. Its magnitude is always positive, so <em>F</em> = 3700 N.
