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worty [1.4K]
4 years ago
13

A block of mass 3 kg slides down a frictionless inclined plane of length 6 m and height 4 m. If the block is released from rest

at the top of the incline, what is its speed at the bottom?
Physics
1 answer:
Ludmilka [50]4 years ago
6 0
(if it's frictionless the length doesn't even matter :) )
It would have the same kinetic energy down as the potential energy up. That is, mgh=\frac{mv^2}{2} or 2gh=v^2 (the mass doesn't even matter). The result is \sqrt{2gh}, so only the height matters really. It is almost 9 (it is \sqrt{80}=4\sqrt{5}).
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What wires allow electrons to flow the easiest?
docker41 [41]
The shortest and straight ones
5 0
3 years ago
A 1200-kg SUV is moving alone a straight highway at 12.0 m/s. Another car, with mass 1800 kg and speed 20.0 m/s, has its center
andreev551 [17]

Answer:

A) d = 24 m

B) 50400 kg.m/s

C) v₀ = 16.8 m/s

D) 50400 kg.m/s. It's equal to the momentum found in part B.

Explanation:

We are given;

Mass of station wagon;m1 = 1200 kg Velocity; V = 12 m/s

Mass of car; m2 = 1800 kg

Velocity of car; v2 = 20 m/s

a ) Let centre of mass of car and station wagon be at a distance d from wagon

Thus,

If we take moment of weight about it, we have;

1200 x d = 1800 x ( 40 - d )

Where, d is the position of the center of mass of the system consisting of the two cars

Thus,

1200d = 72000 - 1800d

1200d + 1800d = 72000

3000 d = 72,000

d = 72,000/3000

d = 24 m

b ) Total momentum= m1•v1 + m2•v2

= (1200 x 12) + (1800 x 20)

= 14400 + 36000

= 50400 kg.m/s

c ) Let speed of centre of mass be v₀

Thus,

v₀ = (m1•v1 + m2•v2)/(m1 + m2)

v₀ = 50400/(1200 + 1800)

v₀ = 50400/3000

v₀ = 16.8 m/s

d) System Total momentum = velocity of centre mass x total mass

Thus,

Total momentum = v₀(m1 + m2)

= 16.8(3000) = 50400 kg.m/s .

This value is equal to what was calculated in part b

8 0
3 years ago
An observer standing near a window 5 m high observe that an object falling downwards is passing across the window in 0.5 s. Find
Valentin [98]

Answer:

Explanation:

An object in free fall, NOT experiencing parabolic motion, has an equation of

h(t)=\frac{1}{2} gt^2+h_0 which says:

The height of an object with respect to time in seconds is equal to the pull of gravity times time-squared plus the height from which it was dropped. Normally we use -9.8 for gravity but you said to use 10, so be it.

For us, h(t) is 5 because we are looking for the height of the window when the object is 5 m off the ground at .5 seconds;

g = 10 m/s/s, and

t = .5sec

5=\frac{1}{2}(-10)(.5)^2+h and

5 = -5(.5)² + h and

5 = -5(.25) + h and

5 = -1.25 + h so

h = 6.25

That's how high the window is above the ground.

8 0
3 years ago
A child pulls a wagon at a constant velocity along a level sidewalk. The child does this by applying a 22 newton force to the wa
Jlenok [28]

Answer:

The answer is 18 N.

Explanation:

A force can be divided into components x and y components. The component along the x-axis is called the horizontal component and along the y-axis is called the vertical component. In this case, as the force is in a horizontal direction and is also known as x-component of force. The x- component of force is  

Fx = Fcosθ

Fx = 22(cos 35°)

Fx = 22 x 0.819

Fx =  18 N

Child's horizontal pull forces are equal to that of frictional resistance force on the wagon.

5 0
3 years ago
How can we calculate force
lutik1710 [3]

To calculate force, use the formula force equals mass times acceleration, or F = m × a. Make sure that the mass measurement you're using is in kilograms and the acceleration is in meters over seconds squared. When you've solved the equation, the force will be measured in Newtons.

8 0
3 years ago
Read 2 more answers
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