Một vật có khối lượng 2 kg rơi tự do xuống đất trong khoảng thời gian 0,5 s. Độ biến thiên động lượng của vật trong khoảng thời gian đó là bao nhiêu ? Cho g = 10 m/s2.

Answer:

I don't know 11 but in no. 10,

The ans is 3.66

Total distance = 10m+30m+15m = 55m

Total time = 5secs+7secs +3secs =15secs

Av speed = d/t =55/15 = 3.66 m/s

Answer:

time period is independent of K.E of particle, it is inversely proportional to specific charge of the particle and it is independent of angle between velocity and magnetic field

Answer:

1. 25 J

2. 250 J

3. 900,000 J

4. 7,500 J

Explanation:

1. The distance the wheelbarrow is tilted, d = 0.5 m

The force used to tilt the wheelbarrow, F = 50 N

The work done, W = F × d

∴ W = 50 N × 0.5 m = 25 J

2. Work done, W = Force × Distance

The applied force, F = 50 N

The distance the sand is moved, d = 5 m

∴ W = 50 N × 5 m = 250 J

3. The work done, W = The load lifted × The height to which the load is lifted

∴ W = 90,000 N × 10 m = 900,000 J

The work done, W = 900,000 J

4. The work output of the skateboard = The work input × Efficiency

Given that the skateboard is an ideal machine, we have;

The work output of the skateboard = The work input = W

W = F × d

F = 15 N, d = 500 m

∴ W = 15 N × 500 m = 7,500 J

The work output of the skateboard = W = 7,500 J.

Answer:

Dynamo

Explanation:

As we all know, there are dynamos in bicycles. When we paddle the cycle, the wheels of the cycle rotates by generating kinetic energy. When the wheels rotate, the dynamo starts to rotate. This makes the motor inside the dynamo rotates and generate electrical energy.

Answer:

density = mass/volume

density=0.8

volume=36

mass=?

0.8=mass/36

mass = 36x0.8=28.8g

Answer:

well, hydropower is using fast-running water as a source of power to power machines or produce electricity, and using water can help make the earth a little cleaner, just like solar energy (energy from the sun). instead of using things like coal, oil, gas which is bad for the earth

Explanation:

Answer:

0.748seconds

Explanation:

s = 1/2 *g*t^2

2.8 = 1/2 * 10* t^2

5.6 = 10 * t^2

0.56 = t^2

t = √0.56

t = 0.7483seconds

Answer:

B. Gamma

Explanation:

The gamma radiation can travel much farther through air than alpha or beta.

Answer:

a. Time = 3.6 seconds

b. Time = 4.4 seconds

Explanation:

Given the following data;

Distance = 180 m

Speed = 50 m/s

a. To find the time;

Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.

Mathematically, speed is given by the formula;

[tex]Speed = \frac{distance}{time}[/tex]

Making time the subject of formula, we have;

[tex]Time = \frac{distance}{speed}[/tex]

Substituting into the equation, we have;

[tex]Time = \frac{180}{50}[/tex]

Time = 3.6 seconds

b. Distance = 220 meters

Speed = 50 m/s

To find the time;

[tex]Time = \frac{distance}{speed}[/tex]

Substituting into the equation, we have;

[tex]Time = \frac{220}{50}[/tex]

Time = 4.4 seconds

Answer:

It's Obusively charles Babbage I guess

Answer:

(a) [tex]\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]

(b) P =  0.816 Watt

Explanation:

(a)

The power radiated from a black body is given by Stefan Boltzman Law:

[tex]P = \sigma AT^4[/tex]

where,

P = Energy Radiated per Second = ?

σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴

T = Absolute Temperature

So the ratio of power at 250 K to the power at 2000 K is given as:

[tex]\frac{P_{250k}}{P_{2000k}}=\frac{\sigma A(250)^4}{\sigma A(2000)^4}\\\\\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]

(b)

Now, for 90% radiator blackbody at 2000 K:

[tex]P = (0.9)(5.67\ x\ 10^{-8}\ W/m^2.K^4)(1\ x\ 10^{-6}\ m^2)(2000\ K)^4[/tex]

P =  0.816 Watt

Answer:

True

Explanation:

Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed, or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight line at a constant speed, when no forces act upon them

Answer:

True po sagot sabihin mo kong mali

Explanation:

Lets say you have a ball in your hand, you raise your hand to just above your head. Now, when you did that you created potential energy that is ready to be released. you drop the ball and the ball bounces a few times off the ground. Now lets say you got a ladder and doubled the ball's height doubling the energy now stored in the ball, when you drop it the ball should bounce much higher after hitting the ground as a result of more energy being released.

Hope this helped.

Given W (work) = 300J

F (force) = 75N

s (displacement) = ?

We know that, W = Fs

So,

300 J = 75N × s

= 300J/75N = s

= 4m = s

So, I traveled 4m.

Answer:

Time, t = 28.87 seconds

Explanation:

Given the following data;

Acceleration = 1.20 m/s²

Distance = 500 meters

Initial velocity = 0 m/s

To find the time to cover the distance, we would use the second equation of motion;

[tex] S = ut + \frac {1}{2}at^{2}[/tex]

Where;

S represents the displacement or height measured in meters.

u represents the initial velocity measured in meters per seconds.

t represents the time measured in seconds.

a represents acceleration measured in meters per seconds square.

Substituting into the equation, we have;

[tex] 500 = 0*t + \frac {1}{2}*(1.2)*t^{2}[/tex]

[tex] 500 = 0 + 0.6*t^{2} [/tex]

[tex] 500 = 0.6t^{2} [/tex]

[tex] t^{2} = \frac {500}{0.6} [/tex]

[tex] t^{2} = 833.33 [/tex]

Taking the square root of both sides, we have;

[tex] t = \sqrt{833.33} [/tex]

Time, t = 28.87 seconds

Answer:

dₒ/dᵢ = 0.32

Explanation:

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

Object height (Hₒ) = 4 mm

Image height (Hᵢ) = 1.25 cm

Ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] =?

Next, we shall convert 4 mm to cm. This can be obtained as follow:

10 mm = 1 cm

Therefore,

4 mm = 4 mm × 1 cm / 10 mm

4 mm = 0.4 cm

Next, we shall determine the magnification of the lens. This can be obtained as follow:

Object height (Hₒ) = 4 mm

Image height (Hᵢ) = 1.25 cm

Magnification (M ) =?

M = Hᵢ/Hₒ

M = 1.25 / 0.4

M = 3.125

Finally, we shall determine the ratio of object distance (dₒ) to image distance (dᵢ). This can be obtained as follow:

Magnification (M) = 3.125

Ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] =?

Magnification (M) = image distance (dᵢ) / object distance (dₒ)

M = dᵢ/dₒ

Invert

1/M = dₒ/dᵢ

1/3.125 = dₒ/dᵢ

dₒ/dᵢ = 0.32

Therefore, the ratio of object distance (dₒ) to image distance (dᵢ) [dₒ/dᵢ] is 0.32

Answer:

, a fundamental property of all matter. It is, in effect, the resistance that a body of matter offers to a change in its speed or position upon the application of a force. The greater the mass of a body, the smaller the change produced by an applied force.

Answer:

The spring constant is 171.43 N/m.

Explanation:

compression in spring, x = 0.07 m

force, F = 12 N

Let the spring constant is K.

Use the formula of the restoring force of the spring

F = K x

12 = K (0.07)

K = 171.43 N/m  

Answer:

coefficient=1.09N/m×g

coefficient=1.09N/0.413g×10m/s square

coefficient=1.09N/4.13N

coefficent=0.263

f= uK

here f is force, u is cofficient of friction , k is normal force

k = mg

f = umg

1.09 = u × 0.41 × 10

u = 1.09 ÷ 4.1

u = 0.26

Answer:

I think the echo sounds do not depend on the direction of the sound and sound the same as the original sound

Explanation:

An echo is defined as a sound that is produced when a sound wave is reflected back from any hard surface and repeated.

Two major application of echo include:

- Bats, fisherman, and dolphins use echoes to detect or identify any object /obstruction.

- Echo is widely used in medical science applications for imaging of human organs such as echocardiography and ultrasound.

I hope this help you!:)

Answer:

So, option(a).

Explanation:

Momentum is the measure of motion of the object.

Momentum is given by the product of mass and the velocity of the object.

(a) It is false.

(b) It is true, momentum is transferred.

(c) It is true, As the momentum of the system is conserved when no external force is applied on the system.

(d) It is true, as the momentum is associated with the velocity of the object.

Answer:

In many vibrating systems the frictional force Ff can be modeled as being proportional to the velocity v of the object: Ff = −cv, where c is called the viscous damping coefficient.

Answer:

A. Object A requires twice the force to stop as Object B.

Explanation:

Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.

Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.

Mathematically, it is given by the formula;

[tex] Acceleration = \frac {Net \; force}{mass} [/tex]

Let's assume the following values;

Mass of object B = 10 kg

Mass of object A = 2 * B = 2 * 10 = 20 kg

Acceleration = 5 m/s²

I. To find the force for B;

[tex] Force = mass * acceleration [/tex]

[tex] Force = 10 * 5 [/tex]

Force B = 50 Newton

II. To find the force for A;

[tex] Force = mass * acceleration [/tex]

[tex] Force = 20 * 5 [/tex]

Force A = 100 Newton

From the calculation, we can deduce that Force A (100 N) is twice or double the value of Force B (50 N).

In conclusion, since object A has twice the mass of object B and both objects are moving at the same speed, object A would require twice the force to stop as Object B.

Answer:

A

Explanation:

The moving object will accelerate as long as a net force is applied. If a net force is not applied, the object will continue to move at a constant speed along the same path in curved spacetime (due to gravity). If the net force continues the velocity of the object will continue to increase until nearly reaching the limit (speed of light).

Answer:

Explanation:

Use the one-dimensional equation for motion

v = v₀ + at and filling in,

v = 0 + (-9.8)(3.32) so

v = -33 m/s (negative because it is going downwards and upwards is positive).

Answer:

【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】

Answer:

6 beats

If one fork beats once and another twice in the same time period

you would hear 1 beat. (Same for 2 and 3 beats).

Answer:

ummm a whole bunch

Explanation: