Score
1 answer:
Answer:
(a) J = 10560 kg-m/s (b) 251.42 N
Explanation:
Given that,
Mass, m = 4400 kg
Initial speed, u = 5.2 m/s
Final speed, v = 7.6 m/s
Time, t = 42 s
(a) Let J be the impulse exerted on the vehicle. Impuse is equal to the change in momentum such as :
J = m(v-u)
J = 4400 (7.6-5.2)
J = 10560 kg-m/s
(b) Impulse = Force × t
Hence, this is the required solution.
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Answer:
1. Reflection
2. travel from one medium to another
3. Same waves to travel in opposite direction.
Explanation:
1. When a wave strikes a solid barrier, it bounces back in the same medium. This wave behavior of bouncing back is known as reflection. Its like a basketball hitting a backboard. The ball bounces back at the same angle as it was incident. ∠i = ∠r
2. For refraction to occur in a wave, the wave must travel from one medium to another. When light travels from through mediums of different optical densities, it bends. The wave bends away normal when it enters from denser medium to rarer medium. The wave bends towards the normal when it enters from rarer to denser medium. The angle of refraction and angle of incidence are related by Snell's law.
3. The formation of standing wave requires two same waves to travel in the opposite direction and interfere. The incident wave and reflected wave when interfere, form standing waves. There waves are also resonances or harmonics. A standing wave oscillates at one place and does not transfers any energy.
Answer:
Linear and rotational Kinetic Energy + Gravitational potential energy
Explanation:
The ball rolls off a tall roof and starts falling.
Let us first consider the potential energy or more specifically gravitational potential energy (;
= mass of the ball,
= acceleration due to gravity,
= height of the roof). This energy comes because someone or something had to do work to take the ball to the top of the roof against the force of gravity. The potential energy is naturally maximum at the top and minimum when the ball finally reaches the ground.
Now, the ball starts to roll and falls off the roof. It shall continue rotating because of inertia (Newton's first law). This contributes to the rotational kinetic energy (;
=moment of inertia of the ball &
= angular velocity).
Finally comes the linear kinetic energy or simply, kinetic energy () which is caused due to the velocity
of the ball.