How would i solve these problems, nobody in my class understands and there is a substitute

Need help with science pls help me!! 40 points

sp2606 [1]

Answer: a. Regularly, you rub your hands for warmth.

b. Some examples are friction from electricity going through a wire or friction from rubbing your hand together.

c. Without friction, we would fall every time we walked. Because there is friction, we can walk normally. Another example is a ball moving across the field. Without friction, the ball would not slow down.

Explanation:

Overall, friction is important to us because we depend on it.

3 0

2 years ago

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An object accelerates at 5 m/s2, over a 3 second time period to a final velocity of 20 m/s. What is the initial velocity?

cricket20 [7]

Using kinematic equation, v =u +at, u= v-at = 20- 3x5 = 5m/s. Initial velocity = 5 m/s

8 0

3 years ago

25 POINTS FOR GOOD ANSWERS!!!!!! BAD ONES WILL BE REPORTED!!!

ololo11 [35]

1 The electric power sector generates most of the electricity in the United States, and the other four sectors consume most of that electricity. ... For example, petroleum provides about 92% of the energy used for transportation, but only 1% of the energy used to generate electricity.

2 In a simple case such as an object resting upon a table, the normal force on the object is equal but in opposite direction to the gravitational force applied on the object (or the weight of the object), that is, , where m is mass, and g is the gravitational field strength (about 9.81 m/s2 on Earth).

3 Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.

4 A performance appraisal is a formal process used to assess an employee's effectiveness and productivity and serves both administrative and developmental purposes. Administratively, it helps guide decision-making regarding employment actions, personnel planning and training and development.

5

any of the basic mechanical devices for applying a force, such as an inclined plane, wedge, or lever.

6 Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force. The model for this is the law of the lever.

7Ratio analysis is used to evaluate various aspects of a company's operating and financial performance such as its efficiency, liquidity, profitability and solvency.

6 0

4 years ago

A 1420-kg car is traveling with a speed of 12.4 m/s. What is the magnitude of the horizontal net force that is required to bring

zzz [600]

Answer:

1419.01436 N

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

$v^2-u^2=2as\\\Rightarrow a=\frac{v^2-u^2}{2s}\\\Rightarrow a=\frac{0^2-12.4^2}{2\times 78}\\\Rightarrow a=-0.98564\ m/s^2$

The force on the car

$F=ma\\\Rightarrow F=1420\times -0.98564\\\Rightarrow F=-1419.01436\ N$

Magnitude of the horizontal net force that is required to bring the car to a halt is 1419.01436 N

3 0

3 years ago

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Some homes that use baseboard heating use copper tubing. hot water runs through and heats the copper tubing, which in turn heats

AlekseyPX

When you heat a certain substance with a difference of temperature $\Delta T$ the heat (energy) you must give to it is
$E(=Q) =mc\Delta T$
where $c$ is the specific heat of that substance (given in J/(g*Celsius))
In this case
$E=645*0.3850*(28.22-13.20) =3729.8 (Joule)$

Observation: the specific heat of a substance is given in J/(g*Celsius) or J/(g*Kelvin) because on the temperature scale a difference of 1 degree Celsius = 1 degree Kelvin

7 0

3 years ago