A positively-charged piece of plastic exerts an attractive force on an electrically neutral piece of paper. This is because: 1.
1 answer:
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49d
<h3>Further explanation</h3>This case is about uniformly accelerated motion.
<u>Given:</u>
The initial speed was v takes distance d to stop after the brakes are applied.
<u>Question:</u>
What is the stopping distance if the car is initially traveling at speed 7.0v?
Assume that the acceleration due to the braking is the same in both cases. Express your answer using two significant figures.
<u>The Process:</u>
The list of variables to be considered is as follows.
The formula we follow for this problem are as follows:
- a = acceleration (in m/s²)
- u = initial velocity
- v = final velocity
- d = distance travelled
Step-1
We substitute v as the initial speed, distance of d, and zero for final speed into the formula.
Both sides are divided by -2d, we get
Step-2
We substitute 7.0v as the initial speed, zero for final speed, and Equation-1 into the formula.
Here d' is the stopping distance that we want to look for.
We crossed out 2 in above and below.
We multiply both sides by d.
We crossed out v^2 on both sides.
Hence, by using two significant figures, the stopping distance if the car is initially traveling at speed 7.0v is 49d.
<h3>Learn more</h3>- Determine the acceleration of the stuffed bear brainly.com/question/6268248
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Keywords: a car traveling at speed v, takes distance d to stop after the brakes are applied, the stopping distance, if the car is initially traveling at speed 7.0v, the acceleration due to the braking is the same, two significant figures.
The gravitational potential energy of the brick is 25.6 J
Explanation:
The gravitational potential energy of an object is the energy possessed by the object due to its position in a gravitational field.
Near the surface of a planet, the gravitational potential energy is given by
where
m is the mass of the object
g is the strength of the gravitational field
h is the height of the object relative to the ground
For the brick in this problem, we have:
m = 8 kg is its mass
g = 1.6 N/kg is the strenght of the gravitational field on the moon
h = 2 m is the height above the ground
Substituting, we find:
Learn more about potential energy:
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a The kinetic energy of an object always has a positive value.
Explanation:
The kinetic energy of an object is the energy possessed by an object due to its motion, and it can be calculated as
where
m is the mass of the object
v is its speed
Let's now analyze each statement:
a The kinetic energy of an object always has a positive value. --> TRUE. In fact, the mass of the object is always positive, and the term is always positive as well, so the kinetic energy is always positive.
b The kinetic energy of an object is directly proportional to its speed. --> FALSE. Looking at the formula, we see that the kinetic energy is proportional to the square of the speed, .
c The kinetic energy of an object is expressed in watts. --> FALSE. Watts is the units for measuring power, while the kinetic energy is measured in Joules, the units for the energy.
d The kinetic energy of an object is a quantitative measure of its inertia. --> FALSE. The inertia of an object depends only on its mass, not on its speed.
e The kinetic energy of an object is always equal to the object’s potential energy. --> FALSE. The potential energy depends on the altitude from the ground, not from the speed, so the two energies can be different.
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