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3 years ago

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Lucia is playing with magnetic toy vehicles. She has two identical toy vehicles (purple and pink) that start on opposite sides o

f a center magnet that cannot move. She moves both vehicles one space closer to the center magnet.??? what

2 answers:

White raven [17]3 years ago

4 0

Here for points dhdjdjdlspeosi

jekas [21]3 years ago

3 0

Answer: The potential energy of both toy vehicles (purple and pink) decreased. Since the pink toy was moved closer to the magnet, it will have less potential energy because of the short distance it will take to travel to the magnet.

Explanation:

Brainliest

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Your friend says that when someone drives a car, they use up energy. You know that this isn’t quite true. Develop an argument ag

Dafna11 [192]

Answer:

Only about 12%–30% of the energy from the fuel you put in a conventional vehicle is used to move it down the road, depending on the drive cycle.

Explanation:

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3 years ago

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A car of mass 875 kg is traveling 30.0 m/s when the driver applies the brakes, which lock the wheels. The car skids for 5.60 s i

AleksAgata [21]

Explanation:

It is given that,

Mass of the car, m = 875 kg

Initial speed of the car, u = 30 m/s

Brakes are applied i.e. v = 0

The car skids for 5.60 s in the positive x - direction before coming to rest, t = 5.6

(a) Acceleration of the car, $a=\dfrac{v-u}{t}$

$a=\dfrac{0-30}{5.6}$

$a=-5.35\ m/s^2$

(b) Force, F = ma

$F=875\ kg\times -5.35\ m/s^2$

F = -4681.25 N

So, the force of 4681.25 N is acting on the car.

(c) Let x is the distance covered by the car. So,

$v^2-u^2=2ax$

$0-u^2=2ax$

$x=\dfrac{-u^2}{2a}$

$x=\dfrac{-(30\ m/s)^2}{2\times -5.35\ m/s^2}$

x = 84.11 meters

So, the distance covered by the car is 84.11 meters. Hence, this is the required solution.

7 0

3 years ago

A car is moving at a speed of 50 km/hour.the driver takes her foot off the accelerator and the car coasts to stop.why?

vodka [1.7K]

Because of the opposing forces on the car like friction because there is no more acceleration

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4 years ago

During her high bar routine from question 2, Gabby Douglas slipped and falls from the high bar, landing on a 10 cm thick gymnast

tankabanditka [31]

a) 122.5 J

b) -122.5 J

c) -1884.6 N

d) -3769.2 N

e) $-753.8 m/s^2$

f) $a=-76.9 g$

Explanation:

a)

The kinetic energy of an object is the energy possessed by the object due to its motion.

Mathematically, it is given by:

$K=\frac{1}{2}mv^2$

where

m is the mass of the object

v is the speed of the object

Here, we want to find the kinetic energy of the head just before hitting the mat.

At that instant, the speed is:

v = 7 m/s

The mass of the head is:

m = 5 kg

So, the kinetic energy is

$K=\frac{1}{2}(5)(7)^2=122.5 J$

b)

According to the work-energy theorem, the work done by a force on an object is equal to the change in kinetic energy of the object:

$W=K_f - K_i$

where

W is the work done

$K_f$ is the final kinetic energy

$K_i$ is the initial kinetic energy

In this problem:

$K_i=122.5 J$ is the kinetic energy of the head just before hitting the mat

$K_f=0 J$ is the final kinetic energy (since the head comes to a stop)

So, the work done by the mat is:

$W=0-122.5 = -122.5 J$

The work is negative because the force exerted by the mat is opposite to the direction of motion of the head.

c)

The work exerted by a force on an object is given by

$W=Fd$

where

F is the force applied

d is the displacement of the object

W is the work done

In this problem:

W = -122.5 J is the work done by the mat on the head

d = 6.5 cm = 0.065 m is the displacement of the head (since it deflects the mat by this amount)

So, the average force exerted by the mat on the head is:

$F=\frac{W}{d}=\frac{-122.5}{0.065}=-1884.6 N$

(the negative sign indicates that the force is in direction opposite to the motion of the head)

d)

The force calculated in part d) represents the average force exerted by the mat on the head:

$F_{avg}=-1884.6 N$

We can assume that as the head first hits the mat, the initial force is zero, then increases at a constant rate up to a peak value of $F_{peak}$ , then it decreases again until the head stops.

In this case, the relationship between average force and peak force is:

$F_{avg}=\frac{0+F_{peak}}{2}$

And therefore, the peak impact force exerted by the mat on the head is:

$F_{peak}=2F_{avg}=2(1884.6)=-3769.2 N$

e)

The peak acceleration of the head can be found by using Newton's second law, which states that:

$F=ma$

where

F is the force on the head

m is the mass of the head

a is the acceleration

Here we have:

F = -3769.2 N is the peak force

m = 5 kg is the mass of the head

So, solving for the acceleration, we find:

$a=\frac{F}{m}=\frac{-3769.2}{5}=-753.8 m/s^2$

f)

The value of the acceleration due to gravity is

$g=9.8 m/s^2$

Here we want to express the peak acceleration of the head in terms of the acceleration due to gravity; so we can write:

$a=Ng$

where

$a=-753.8 m/s^2$ is the peak acceleration

N is the ratio between the peak acceleration and the gravity acceleration

Solving for N,

$N=\frac{a}{g}=\frac{-753.8}{9.8}=-76.9$

This means that the peak acceleration can be written as

$a=-76.9 g$

6 0

3 years ago

Which two forces are always equal and opposite for an object on a surface?

Kisachek [45]

Answer:

Suppose any object with mass in our planet.

The object will be affected by the gravitational force, that pulls the object down. Now, a table in your dining room is also affected by this force, but the table is in a surface (the ground) and it does not move.

We know that if an object does not move, then the net force acting on it is equal to zero, this means that there is a force equal and opposite ot the gravitational force.

This force is the normal force, that the ground applies on the table. This force comes as a "response" to the table pushing the ground (By 3rd Newton's law).

So two forces that are always equal and opposite are the forces caused by this law.

5 0

3 years ago