Stella is driving down a steep hill. She should keep her car __________ to help _________. a. light, it speed up in a higher b.
2 answers:
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Answer:
1. Mechanical energy = 298.4 Joules.
2. Mechanical energy = 2140 Joules.
3. Mechanical energy = 0.2838 Joules.
Explanation:
Kinetic energy can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;
Where;
K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
Potential energy can be defined as an energy possessed by an object or body due to its position.
Mathematically, potential energy is given by the formula;
Where,
P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Given the following data;
1. Kinetic energy = 182.2 J
Potential energy = 116.2 J
To find the mechanical energy;
Mechanical energy = kinetic energy + potential energy
Mechanical energy = 182.2 + 116.2
Mechanical energy = 298.4 Joules.
2. Mass = 40kg
Velocity = 3m/s
Height = 5m
We know that acceleration due to gravity is equal to 9.8m/s²
To find the mechanical energy;
We would determine the kinetic and potential energy respectively.
K.E = ½mv²
K.E = ½*40*3²
K.E = 20*9
K.E = 180 Joules.
P.E = mgh
P.E = 40*9.8*5
P.E = = 1960 Joules
Mechanical energy = K.E + P.E
Mechanical energy = 180 + 1960
Mechanical energy = 2140 Joules.
3. Mass = 0.002kg
Height = 3m
Velocity = 15m/s
To find the mechanical energy;
K.E = ½mv²
K.E = ½*0.002*15²
K.E = 0.001*225
K.E = 0.225 Joules.
P.E = mgh
P.E = 0.002*9.8*3
P.E = = 0.0588 Joules
Mechanical energy = K.E + P.E
Mechanical energy = 0.225 + 0.0588
Mechanical energy = 0.2838 Joules.
The acceleration of the runner in the given time is 2.06m/s².
Given the data in the question;
Since the runner begins from rest,
- Initial velocity;
- Final velocity;
- Time elapsed;
Acceleration of the runner;
Velocity is the speed at which an object moves in a particular direction.
Acceleration is simply the rate of change of the velocity of a particle or object with respect to time. Now, we can see the relationship from the First Equation of Motion
Where v is final velocity, u is initial velocity, a is acceleration and t is time elapsed.
To determine the acceleration of the runner, we substitute our given values into the equation above.
Therefore, the acceleration of the runner in the given time is 2.06m/s².
Learn more about Equations of Motion: brainly.com/question/18486505