6d A boy pushes his little brother on a sled. The sled accelerates from rest to (4 m/s). If the combines of his brother and the sled is (40.0 kg) and (20 W) of power is developed, how long time does the boy push the sled?​

Answers

Answer 1

Answer:

16 s

Explanation:

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

Mass (m) = 40 Kg

Velocity (v) = 4 m/s

Power (P) = 20 W

Time (t) =?

Next, we shall determine the energy. This can be obtained as follow:

Mass (m) = 40 Kg

Velocity (v) = 4 m/s

Energy (E) =?

E = ½mv²

E = ½ × 40 × 4²

E = 20 × 16

E = 320 J

Finally, we shall determine the time. This can be obtained as follow:

Power (P) = 20 W

Energy (E) = 320 J

Time (t) =?

E = Pt

320 = 20 × t

Divide both side by 20

t = 320 / 20

t = 16 s

Thus, the time is 16 s


Related Questions

with respect to air the refractive index of ice is 1.31 and that of rock salt is 1.54 calculate the refractive index of rock salt with respect to ice​

Answers

Answer:

1.17

Explanation:

Given that,

The refractive index of ice wrt air = 1.31

The refractive index of rock salt wrt air = 1.54

We need to find the refractive index of rock salt with respect to ice.

We know that,

refractive index = (speed of light in air or vaccum)/( speed of light in that medium)

So,

The speed of light in ice = c/(1.31)

The speed of light in rock salt = c/(1.54)

So, the refractive index of rock salt with respect to ice​ is :

[tex]\mu=\dfrac{1.54}{1.31}\\\\=1.17[/tex]

So, the required refractive index of rock salt wrt ice is 1.17.

Which type of wave causes particles of matter to vibrate in a direction
perpendicular to the direction of its motion?
O A. Sound
B. Transverse
C. Longitudinal
D. Compression

Answers

It’s transverse so the answer is B

Answer:

C.) Longitudinal

A car takes a full round of journey in a roundabout with constant speed, as the driver got confused with the route. Can we consider it as a uniform motion? Why?

Answers

Answer: The given statement is True

Explanation:

A uniform motion is defined as the motion where an object is moving at a constant speed.

A non-uniform motion is defined as the motion where an object keeps changing its position and does not move at a constant speed.

We are given:

A car takes a full round of journey in a roundabout with constant speed

As the speed remains constant in a circular path, it is considered a uniform motion.

Hence, the given statement is True

Which energy store is increased when an object is heated?

Answers

Answer:

Kinetic Energy

Explanation:

HELPPP ILL GIVE BRAINLIST

Answers

Answer:

1= Kidneys

2= Ureters

3=Bladders

4=Urethra

Explanation:

Functions of kidney: Regulations of water balances, excretions of nitrogenous wastes(urea)

Functions of Liver: Detoxifications, protein synthesis

Functions of Skin: Temperature regulations, Metabolic functions, Excretion

Functions of lungs: Respiration, Water balance regulations

Tip: If you want faster and correct answers you should label your questions under the correct subject.

If the amplitude of a sound wave is increased by a factor of four,how does the energy carry by the sound wave in each time interval change?

Answers

Answer:

The energy will be increased by a factor 16

Explanation:

Mathematically, we have it that the energy carried by the sound wave is directly proportional to the square of the amplitude

So we have it that;

E = k * A^2

where E is the wave energy

K is the constant value

A is the amplitude value

So;

If E1 = k * (A1)^2

E2 = k * (A2)^2

But A2 = 4A1

E2 = k * (4A1)^2

E2 = k * 16(A1)^2

Divide E2 by E1

E2/E1 = k/k * 16(A1)^2/(A1)^2

E2/E1 = 16

E2 = 16 * E1

so simply, the energy will be increased by a factor of 16

Ball X has a mass of 8kg and is moving toward ball Y (which is sitting still) at 2m/s. After they collide, ball X is
sitting still. How fast is ball Y moving after the collision if it has a mass of 4kg?

Answers

Answer:

v = 4 m/s

Explanation:

Given :

Ball X :

Mass, m1 = 8kg ;

Initial Velocity, u1 = 2 m/s

Final velocity, v1 = 0

Ball Y:

Mass, m2 = 4kg ;

Initial Velocity, u2 = 0 m/s

Final velocity, v2 = v

(m1u1 + m2u2) = (m2v2 + m1v1)

(8*2 + 4*0) = (4*v + 4*0)

16 + 0 = 4v + 0

16 = 4v

v = 16 / 4

v = 4 m/s

Answer:

Explanation:

This is the Law of Momentum Conservation which for us looks like this:

[tex][m_xv_x+m_yv_y]_b=[m_xv_x+m_yv_y]_a[/tex] and that should look familiar to you if this is what you are doing in physics. Filling in our particular info:

[(8.0 × 2.0)+ (4.0 × 0.0)] = [(8.0 × 0.0) + (4.0v)] and

16 + 0 = 0 + 4.0v and

16 = 4.0v so

v = 4.0 in the direction of ball X

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