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AURORKA [14]
3 years ago
7

Please Help Me

Physics
1 answer:
JulijaS [17]3 years ago
7 0

1. a=Δv/Δt=(v-vo)/t=(0-25)/5=-25/5=-5 m/s²

The "-" sign shows us that the car has a slow motion


2.a=Δv/Δt=(v-vo)/t=(10-0)/4=10/4=2,5 m/s²


3.they do not have acceleration because they go at constant speed


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Energy Conservation With Conservative Forces: If a spring-operated gun can shoot a pellet to a maximum height of 100 m on Earth,
crimeas [40]

Answer:

h' = 603.08 m

Explanation:

First, we will calculate the initial velocity of the pellet on the surface of Earth by using third equation of motion:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity on the surface of earth = - 9.8 m/s² (negative sign due to upward motion)

h = height of pellet = 100 m

Vf = final velocity of pellet = 0 m/s (since, pellet will momentarily stop at highest point)

Vi = Initial Velocity of Pellet = ?

Therefore,

(2)(-9.8 m/s²)(100 m) = (0 m/s)² - Vi²

Vi = √(1960 m²/s²)

Vi = 44.27 m/s

Now, we use this equation at the surface of moon with same initial velocity:

2g'h' = Vf² - Vi²

where,

g' = acceleration due to gravity on the surface of moon = 1.625 m/s²

h' = maximum height gained by pellet on moon = ?

Therefore,

2(1.625 m/s²)h' = (44.27 m/s)² - (0 m/s)²

h' = (1960 m²/s²)/(3.25 m/s²)

<u>h' = 603.08 m</u>

4 0
3 years ago
A pendulum has 294 J of potential energy at the highest point of its swing. How much kinetic energy will it have at the bottom o
baherus [9]

Newton's law of conservation states that energy of an isolated system remains a constant. It can neither be created nor destroyed but can be transformed from one form to the other.


Implying the above law of conservation of energy in the case of pendulum we can conclude that at the bottom of the swing the entire potential energy gets converted to kinetic energy. Also the potential energy is zero at this point.


Mathematically also potential energy is represented as


Potential energy= mgh


Where m is the mass of the pendulum.


g is the acceleration due to gravity


h is the height from the bottom z the ground.


At the bottom of the swing,the height is zero, hence the potential energy is also zero.


The kinetic energy is represented mathematically as


Kinetic energy= 1/2 mv^2


Where m is the mass of the pendulum


v is the velocity of the pendulum


At the bottom the pendulum has the maximum velocity. Hence the kinetic energy is maximum at the bottom.


Energy can neither be created e destroyed. It can only be transferred from one form to another. Implying this law and the above explainations we conclude that at the bottom of the pendulum,the potential energy=0 and the kinetic energy=294J as the entire potential energy is converted to kinetic energy at the bottom.



6 0
4 years ago
50 grams of ice cubes at -15°C are used to chill a water at 30°C with mass mH20 = 200 g. Assume that the water is kept in a foam
Arada [10]

Answer : The final temperature is, 25.0^oC

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

q_1=-q_2

m_1\times c_1\times (T_f-T_1)=-m_2\times c_2\times (T_f-T_2)

where,

c_1 = specific heat of ice = 2.09J/g^oC

c_2 = specific heat of water = 4.18J/g^oC

m_1 = mass of ice = 50 g

m_2 = mass of water = 200 g

T_f = final temperature = ?

T_1 = initial temperature of ice = -15^oC

T_2 = initial temperature of water = 30^oC

Now put all the given values in the above formula, we get:

50g\times 2.09J/g^oC\times (T_f-(-15))^oC=-200g\times 4.184J/g^oC\times (T_f-30)^oC

T_f=25.0^oC

Therefore, the final temperature is, 25.0^oC

5 0
3 years ago
What physical quantity is a measure of the amount of inertia an object has?
satela [25.4K]
Mass is the physical quantity
3 0
4 years ago
Calculate the change in length of a Pyrex glass dish (Coefficient of linear expansion for Pyrex is 3 * 10-6 / oC) that is 0.25 m
DIA [1.3K]

9*10^{-5} m

Explanation:

Step 1:

We are given the initial length of the Pyrex glass dish at a particular temperature and need to calculate the change in the length when the temperature changes by 120° C. The coefficient of linear expansion of Pyrex is provided.

Step 2:

Change in length = Coefficient of linear expansion * Change in temperature * Initial length

Step 3:

Coefficient of linear expansion = 3*10^{-6} /°C

Change in temperature = 120°C = 120 K

Initial length = 0.25 m

Step 4:

Change in length = 3*10^{-6} * 120 * 0.25 = 9*10^{-5} m

8 0
3 years ago
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