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3 years ago

An object is moving in the absence of a net force. Which of the following best describes the object's motion? -please help?

2 answers:

7 0

You can solve this by using Newton's First Law or Newton's Second Law.

1) Newton's First Law or Inertia Law states that in the abscense of a net force acting over an object, this will not chage its state of movement, i.e it will remain at rest (if it is no moving) or with uniform movement (if the object is moving).

2) Newton's Second Law: Net force = mass * acceleration => acceleration = net force / mass = 0 / mass = 0.

Zero accelerations means rest or uniform movement.

First Law is implicit in Second Law.

anzhelika [568]3 years ago

7 0

There are two cases in which no net force is being applied on an object:
1) The object is stationary
2) The object is not accelerating; that is, the magnitude or direction of its velocity is not changing.
Because this question requires the object to be in motion, the velocity of this object must be constant but non-zero.
Therefore, the correct option would be the one where the velocity is constant and in a straight line. (circular motion means the velocity's direction is constantly changing, thus the velocity is not constant)

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A rubber ball is dropped from a height of 8m. After strikingthe floor, the ball bounces to a height of 5m. a. If the ball had bo

kifflom [539]

Answer:

a) This means the collision between the ball and the floor is elastic.

b) This points to a perfectly inelastic collision between the ball and the floor as they stick together after collision

c) Check Explanation.

Explanation:

Collision of bodies are analysed according to whether both momentum and kinetic energy of the system is conserved, that is, if these two quantities before collision are equal to their values after collision.

In all types of collisions, momentum is usually conserved, but kinetic energy is conserved only in an elastic collision.

A ball dropped from a height of 8 m bounces up back to a height of 5 m.

a. If the ball had bounced to a height of 8m, how would you describe the collision between the ball and the floor?

The ball not bouncing back to a height of 8 m shows energy loss at some point in the total motion of the ball (most likely at the collision). If kinetic energy was conserved, the ball would bounce back up to the height at which it fell from (8 m) after the collision with the floor.

b. If the ball had not bounced at all, how would you describe the collision between the ball and the floor?

If the ball had not bounced at all, this means it lost all of its kinetic energy to the floor, and this points to a perfectly inelastic collision between the ball and the floor as they stick together after collision.

c. What happened to the energy lost by the ball during thecollision?

The energy lost during the collision is converted to another form, most likely responsible for some deformation on the ball & a minute deformation on the floor, converted to some form of heat as a result of the collision or into sound energy, usually, it's a combination of all This!

Hope this Helps!!!

5 0

4 years ago

A piece of charcoal used for cooking is found at the remains of an ancient campsite. A 1.09 kg sample of carbon from the wood ha

fgiga [73]

Answer:

t = 17199 years

Explanation:

given,

mass of sample = 1.09 Kg

Activity of living material = 15 decays / min /g

Activity of living material = 15 x 1000 decays /min /kg

Activity of living material per 1.09 kg A = 1.09 x 15 x 1000 decays / min

Activity of after time t is A ' = 2020

half life = 57300 years

desegregation constant

λ = 0.693 / 5700

$A'= A e^{-\lambda\ t}$

$A'= 1.09 \times 15 \times 1000 e^{-\lambda\ t}$

$2020= 1.09 \times 15 \times 1000 e^{-\dfrac{0.693}{5700}\times t}$

$0.124=e^{-\dfrac{0.693}{5700}\times t}$

taking ln both side

$\dfrac{0.693}{5700}\times t = 2.09$

t = 17199 years

5 0

3 years ago

Two concentric circular loops of wire lie on a tabletop, one inside the other. The inner wire has a diameter of 20.0 cm and carr

Harrizon [31]

Answer:

Explanation:

Magnetic field due to circular wire at the center = μ₀ I / 2 r

I is current and r is radius . μ₀ = 4π x 10⁻⁷.

field B₁ due to inner loop

B₁ = 4π x 10⁻⁷ x 12 / 2 x .20

= 376.8 x 10⁻⁷

Field due to outer loop

B₂ = 4π x 10⁻⁷ x I / 2 x .30

For equilibrium

B₁ = B₂

376.8 x 10⁻⁷ = 4π x 10⁻⁷ x I / 2 x .30

I = 18 A.

The direction should be opposite to that in the inner wire . It should be anti-clockwise.

4 0

3 years ago

Froghoppers may be the insect jumping champs. These 6-mm-long bugs can spring 70 cm into the air, about the same distance as the

earnstyle [38]

Answer:

This is about 176 times the weight of the froghopper.

Explanation:

the grasshopper converts kinetic energy into earth gravitational potential energy

u=mgh

u=12*10^-3*9.8*0.7

=8.23*10^-2

using the Work energy principle

equating the kinetic energy to the potential energy

k +U+w=K2+u2

K+0+0=0+U2

k=8.23*10^-2

force exerted by the grasshopper on the round will be given by tis equation

(F-mg)Ycos $\alpha$ =k

(F-12*10^-3*9.8)*0.004cos 0=8.23*10^-2

F=20.7N

from newtons third law of motion, action and reaction are equal and opposite

F=-20.7N

comparing the forces by the two bodies

F:mg

-20.7:-12*10^-3*9.8

the magnitude of the force applied by the grasshopper is found to be 176 times the gravitational force

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3 years ago

When an electron in a certain excited energy level in a one-dimensional box of length 2.00 Å makes a transition to the ground st

Fiesta28 [93]

Answer:

Calculate the wavelength associated with an electron with energy 2000 eV.

Sol: E = 2000 eV = 2000 × 1.6 × 10–19 J

5 0

3 years ago