Assume the motion when you are in the car or in the school bus to go to the school.
To describe the motion the first thing you need is a point of reference. Assume this is your house.
This should be a description:
- When you are sitting and the car has not started to move you are at rest.
- The car starts moving from rest, gaining speed, accelerating. You start to move away from your house, with a positive velocity (from you house to your school) and positive acceleration (velocity increases).
- The car reaches a limit speed of 40mph, and then moves at constant speed. The motion is uniform, the velocity is constant, positive, since you move in the same direction), and the acceleration is zero.
- When the car approaches the school, the driver starts to slow down. Then, you speed is lower but yet the velocity is positive, as you are going in the same direction. The acceleration is negative because it is in the opposite direction of the motion.
- When the car stops, you are again at rest: zero velocity and zero acceleration.
- In all the path your velocity was positive, constant at times (zero acceleration) and variable at others (accelerating or decelerating).
- When you comeback home, then you can start to compute negative velocities, as you will be decreasing the distance from your point of reference (your house).
Answer:
Car B has a mass of 800 kg.
General Formulas and Concepts:
<u>Momentum</u>
Law of Conservation of Momentum:
Explanation:
<u>Step 1: Define</u>
<em>Identify variables</em>
[Given] m₁ = 1200 kg
[Given] v₁i = 10 m/s
[Solve] m₂
[Given] v₂i = 0 m/s
[Given] vf = 6 m/s
<u>Step 2: Solve for m₂</u>
- Substitute in variables [Law of Conservation of Momentum]: (1200 kg)(10 m/s) + m₂(0 m/s) = (1200 kg + m₂)(6 m/s)
- Multiply: 12000 kg · m/s = (1200 kg + m₂)(6 m/s)
- Isolate m₂ term: 2000 kg = 1200 kg + m₂
- Isolate m₂: 800 kg = m₂
Answer:
The acceleration of the spacecraft is 16,367.62 miles/hr²
Explanation:
Given;
thrust of the spacecraft, F = 5.31 x 10⁶ N
mass of the spacecraft, m = 5,760,000 lbm = 2612692.051 kg
The acceleration of the spacecraft in m/s² is given by Newton's second law of motion;
F = ma
a = F / m
The acceleration in miles per hour square is given by;
Therefore, the acceleration of the spacecraft is 16,367.62 miles/hr²
Answer:
The football leaves with the velocity, u = 15.68 m/s
Explanation:
Given data,
The football bounces back up off the ground and is airborne for, t = 3.2 s
Let the football bounces back up off the ground in the vertical direction
The formula for time of flight is given by,
t = 2u /g
∴ u = gt / 2
Substituting the values,
u = 9.8 x 3.2 / 2
u = 15.68 m/s
Hence, the football leaves with the velocity, u = 15.68 m/s