Answer:
a.2.5x 10^3 m/s
b.mr=48kg/s
Explanation:
A rocket is moving away from the solar system at a speed of 7.5 ✕ 103 m/s. It fires its engine, which ejects exhaust with a speed of 5.0 ✕ 103 m/s relative to the rocket. The mass of the rocket at this time is 6.0 ✕ 104 kg, and its acceleration is 4.0 m/s2. What is the velocity of the exhaust relative to the solar system? (B) At what rate was the exhaust ejected during the firing?
velocity of the exhaust relative to the solar system
velocity of the rocket -velocity of the exhaust relative to the rocket.
7.5 ✕ 103 m/s-5.0 ✕ 103 m/s
2.5x 10^3 m/s
. b we will look for the thrust of the rocket
T=ma
T=6.0 ✕ 104 kg*4.0 m/s2
T=2.4*10^5N
f=mass rate *velocity of the exhaust
T=2.4*10^5N=mr*5.0 ✕ 10^3 m/s
mr=2.4*10^5N/5.0 ✕ 10^3
mr=48kg/s
In collision that are categorized as elastic, the total kinetic energy of the system is preserved such that,
KE1 = KE2
The kinetic energy of the system before the collision is solved below.
KE1 = (0.5)(25)(20)² + (0.5)(10g)(15)²
KE1 = 6125 g cm²/s²
This value should also be equal to KE2, which can be calculated using the conditions after the collision.
KE2 = 6125 g cm²/s² = (0.5)(10)(22.1)² + (0.5)(25)(x²)
The value of x from the equation is 17.16 cm/s.
Hence, the answer is 17.16 cm/s.
<u>Complete Question:</u>
Devon has several toy car bodies and motors. The motors have the same mass, but they provide different amounts of force, as shown in this table.
The bodies have the masses shown in this table (refer attached figure).
Which motor and body should Devon use to build the car with the greatest acceleration?
motor 1, with body 1
motor 1, with body 2
motor 2, with body 1
motor 2, with body 2
<u>Answer:</u>
Devon should build the car with motor 2 and body 1 for having the greatest acceleration.
<u>Explanation:</u>
As per Newton's second law of motion, the acceleration of any object is directly proportional to the force on the object and inversely proportional to the mass of the object.
It can be seen that motor 2 has greater force than the force provided by motor 1. Similarly, the mass of body 1 is found to be lesser compared to mass of body 2. So,

It gives, the system with motor 2 and body 1 the maximum acceleration. So the car should be built with motor 2 and body 1.
Answer:


Explanation:
m = Mass of each the cars = 
= Initial velocity of first car = 3.46 m/s
= Initial velocity of the other two cars = 1.4 m/s
v = Velocity of combined mass
As the momentum is conserved in the system we have

Speed of the three coupled cars after the collision is
.
As energy in the system is conserved we have

The kinetic energy lost during the collision is
.
The potential energy of a swing is greatest at the top of the swing. (Point A).