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3 years ago

The driver of a car traveling at 21 m/s applies the brakes and decelerates at the rate of -3.8 m/s. (a) How long does it

Physics

1 answer:

ANEK [815]3 years ago

6 0

Answer:

105/19

Explanation:

it may exppressed in negative if the velocity is not negative

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PLZ HELP I DONT GET IT

GaryK [48]

Answer:

0.1 L

Explanation:

From the question given above, we obtained the following data:

Initial volume (V₁) = 0.05 L

Initial Pressure (P₁) = 207 KPa

Final pressure (P₂) = 101 KPa

Final volume (V₂) =?

We can obtain the new volume (i.e the final volume) of the gas by using the Boyle's law equation as illustrated below:

P₁V₁ = P₂V₂

207 × 0.05 = 101 × V₂

10.35 = 101 × V₂

Divide both side by 101

V₂ = 10.35 / 101

V₂ = 0.1 L

Thus, the new volume of the gas is 0.1 L

6 0

3 years ago

Plus and minus signs are used in one-dimensional motion to indicate direction. What is the sign of an acceleration that reduces

ladessa [460]

Answer:

Positive sign for negative velocity and minus sing for positive velocity

Explanation:

In the case of the negative velocity, the sign of the acceleration that reduces its magnitude is the positive sign, since being in the opposite direction to the movement indicates a deceleration or braking. In the case of the positive velocity, the sign of the acceleration that reduces its magnitude is the negative sign, since being in the opposite direction to the movement indicates a deceleration or braking. We observe that there will always be a reduction in the magnitude of the velocity if the acceleration goes in the opposite direction.

8 0

3 years ago

A projectile is thrown with an initial speed vo = 25.0 m/s at an initial angle with the horizontal ao = 45.0. a . Find the time

Natali [406]

Answer:

See the explanation below

Explanation:

To solve this problem we must decompose the initial speeds into x & y.

$v_{o}_{x}=25*cos(45)=17.67[m/s]\\v_{o}_{y}=25*sin(45)=17.67[m/s]\\$

The acceleration of gravity is equal to g = 9.81[m/s^2] downward.

The maximum height is when the velocity of the projectile is zero in the component y, that is, it will not be able to go higher, by means of the following kinematic equation we can find that time, for that specific condition.

$v_{y}=(v_{y})_{0}+a*t\\0 = 17.67 - 9.81*t\\17.67 = 9.81*t\\t=1.8 [s]$

Note: Acceleration is taken as negative as it is directed downwards.

The position in the x component can be found using the following kinematic equation

$x=(v_{x})_{o}*t\\x=17.67*1.8\\x=31.82[m]$

The position in the y component can be found using the following kinematic equation

$y =(v_{y})_{o}*t+\frac{1}{2} *g*t^{2} \\y=17.67*1.8-0.5*9.81*(1.8)^{2}\\ y=15.91[m]$

Since the motion on the X-axis is at constant speed, there is no acceleration, so the only acceleration that exists is due to gravity

In the attached image we can see, the projectile with the vectors of acceleration and velocity.

7 0

3 years ago

A 2-kg ball is thrown at a speed of ____, exhibits 25j of kinetic energy.

bogdanovich [222]

Answer:

A 2-kg ball is thrown at a speed of 5 m/s, exhibits 25 J of kinetic energy.

Explanation:

Given that,

The mass of a ball, m = 2 kg

Kinetic energy of the ball, K = 25 J

We need to find the speed of the ball. The formula for the kinetic energy is given by :

$K=\dfrac{1}{2}mv^2\\\\v=\sqrt{\dfrac{2K}{m}} \\\\v=\sqrt{\dfrac{2\times 25}{2}} \\\\v=5\ m/s$

So,

A 2-kg ball is thrown at a speed of 5 m/s, exhibits 25 J of kinetic energy.

3 0

3 years ago

A child squeezes a pillow over his ears during and thunderstorm. Which wave interaction helps decrease the sound of the thunder?

Anastasy [175]

Answer:

Absorption

Explanation:

8 0

3 years ago