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3 years ago

Why is Vy negative and not positive because I solved it and it resulted in a positive number?

Physics

1 answer:

11Alexandr11 [23.1K]3 years ago

8 0

Explanation:

You are given the initial velocity, the displacement, and the acceleration. You're looking for the final velocity. So you use the equation:

v² = v₀² + 2aΔy

When you solve for v, you take the square root. Your calculator will return a positive answer, but there are actually two possible answers: positive and negative.

v = ±√(v₀² + 2aΔy)

You must use the physical context of the problem. If we take up to be the positive direction, then v must be negative, since the projectile is moving down.

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A thin, light wire 75.1 cm long having a circular cross section 0.555 mm in diameter has a 25.4 kg weight attached to it, causin

seraphim [82]

Answer:

(a) 3.23×10⁸ N/m²

(b) 1.46×10⁻³

(c) 2.21×10¹¹ N/m²

Explanation:

(a) Stress = Force/Area.

Stress = F/A................ Equation 1

But,

F = mg................. Equation 2

Where m = mass, and g = acceleration due to gravity

A = πd²/4................. Equation 3

d = diameter of the circular cross section.

Substitute equation 2 and equation 3 into equation 1

Stress = 4mg/πd²............. Equation 4

Given: m = 25.4 kg, d = 0.555 mm = 0.000555 m

Constant: g = 9.8 m/s², π = 3.142

Substitute these values into equation 4

Stress = 4(25.4)(9.8)/(3.142×0.00555²)

Stress = 995.68/(3.08×10⁻⁶)

Stress = 3.23×10⁸ N/m²

(b)

Strain = ΔL/L.............. Equation 5

Where ΔL = extension, L = Length.

Given: ΔL = 1.1 mm = 0.0011 m, L = 75.1 cm = 0.751 m

Substitute into equation 5

Strain = 0.0011/0.751

Strain = 1.46×10⁻³.

(c)

Young modulus = Stress/Strain

Young modulus = 3.23×10⁸/ 1.46×10⁻³

Young modulus = 2.21×10¹¹ N/m²

3 0

3 years ago

Extend the life of your __________ by avoiding fast starts, stops and sharp turns.

skelet666 [1.2K]

Answer:

Tires.

Explanation:

There are the few steps which are discussed below should be taken to increase or extend the life of tires.

(1) Avoid fast starts: Fast start of the vehicle will increase the pressure on the tires due to the friction between the tires and the road will decrease the life of tires.

(2) Avoid fast stop: Fast stop of the vehicle will also increase the pressure on the tires due to the friction between the tires and the road will decrease the life of tires.

(3) Avoid sharp turns: The alignment of the wheels and tires are in such a way that they work properly when vehicle is drive in a straight path but sharp turn will increase the uneven pressure on the tires will lead to decrease the life of tires.

Therefore, the life of tires can be extend by avoiding all the above mention actions such as fast stop, start and sharp turns.

5 0

3 years ago

A book falls off a shelf that is 10.0 m tall. What is the velocity at which the book hits the ground?

Elena L [17]

Answer:

14 m/s

Explanation:

The motion of the book is a free fall motion, so it is an uniformly accelerated motion with constant acceleration g=9.8 m/s^2 towards the ground. Therefore we can find the final velocity by using the equation:

$v^2 = u^2 + 2gd$

where

u = 0 is the initial speed

g = 9.8 m/s^2 is the acceleration

d = 10.0 m is the distance covered by the book

Substituting data, we find

$v=\sqrt{0^2 + 2(9.8 m/s^2)(10.0 m)}=14 m/s$

8 0

3 years ago

Oil having a density of 922kg/m^3 floats on water. A rectangular block of wood 3.97 cm high and with a density of 963 kg/m^3 flo

Blizzard [7]

Explanation:

For the equilibrium:

\rho_{wood}gh-\rho_{oil}g(h-x)-\rho_{water}gx=0ρ

wood

gh−ρ

oil

g(h−x)−ρ

water

gx=0

\rho_{wood}h-\rho_{oil}(h-x)-\rho_{water}x=0ρ

wood

h−ρ

oil

(h−x)−ρ

water

x=0

(974)(3.97)-928(3.97-x)-1000x=0(974)(3.97)−928(3.97−x)−1000x=0

x=2.54\ cmx=2.54 cm

3 0

2 years ago

Please HELP ME If the motion of an object changes, what must be true about the forces acting on that object?

atroni [7]

Answer:

If there is a net force acting on an object, the object will have an acceleration and the object's velocity will change. ... Newton's second law states that for a particular force, the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object.

Explanation:

4 0

3 years ago

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