What part of your daily routine can be changed to help the climate change crisis?

A skateboarder is skating back and forth on the halfpipe as seen below. As he skates his energy transforms from potential energy

egoroff_w [7]

Answer:

Friction and air resistance cause some of his kinetic energy to be “lost”. This makes him slow down.

Explanation:

The law of conservation of energy states that in absence of frictional forces, the mechanical energy of an object (given by the sum of its kinetic and potential energy) is conserved. In such a situation, the skateboarder would never stop his motion, because potential energy is continuously converted into kinetic energy and vice-versa, but the total energy remains the same so he would never stop.

In a real world, however, this is not true. In fact, in a real world some frictional force are present, in particular:

- friction: this force is due to the contact between the skateboard and the surface of the halfpipe, and its direction is always opposite to the motion of the skateboarder

- Air resistance: this force is due to the resistance opposed by the molecules of air that the skateboarder meets during his motion, and its direction is also opposite to the motion of the skateboarder

This two forces are said to be non-conservative forces, which means that they cause some of the mechanical energy of the skateboarder to be "lost", in the sense that it is dissipated as heat and it is no longer available for the skateboarder.

Therefore, the correct option is

Friction and air resistance cause some of his kinetic energy to be “lost”. This makes him slow down.

7 0

3 years ago

A spacecraft of mass 1500 kg orbits the earth at an altitude of approximately 450 km above the surface of the earth. Assuming a

PSYCHO15rus [73]

Answer:

1.28 x 10^4 N

Explanation:

m = 1500 kg, h = 450 km, radius of earth, R = 6400 km

Let the acceleration due to gravity at this height is g'

g' / g = {R / (R + h)}^2

g' / g = {6400 / (6850)}^2

g' = 8.55 m/s^2

The force between the spacecraft and teh earth is teh weight of teh spacecraft

W = m x g' = 1500 x 8.55 = 1.28 x 10^4 N

8 0

3 years ago

A constant net torque is applied to a rotating object. Which of the following best describes the object's motion? A constant net

ahrayia [7]

Answer:

The object will rotate with constant angular acceleration

Explanation:

According to the Newton's Second Law for Whenever there is more than one torque acting on a rigid body that posses fixed axis, the moment of inertia as well as the angular acceleration is equals or proportional to the summation of the torques. It gives details on the relationship between rotational kinematics and torque as well as moment of inertia. This can be represented by the below equation.

∑iτi=Iα.

.Therefore when constant net torque is applied to object that is rotating, the object will rotate with constant angular acceleration

7 0

3 years ago

What happens to the reaction 2 N O 2 in equilibrium with N 2 O 4 plus 57.3 kilojoules when the temperature of the reaction is in

Burka [1]

Answer:

More reactant forms.

Explanation:

Given reaction is,

$2NO_{2}$ ⇒ $N_{2} O_{4}+57.3 KiloJoules$ per mole

This is an Exothermic Reaction,(ΔE=-57.3KJper mole)

We know the equilibrium point of all Exothermic reactions moves leftward and more reactant is formed at the equilibrium.

Reason:

As heat is being produced in the reaction the additional heat(57.3KJpermole) can be thought of as a product of the reaction.

So,if you increase the temperature ,you provide heat energy,

(in other words heat energy is given) and hence the concentration of the products increases.

So, with respect to LeChateliers Principle,

As the concentration of products is increased by external means,more of the reactants are produced at the equilibrium of the reaction.

Therefore amount of reactants increases as more reactant forms.

3 0

2 years ago

Read 2 more answers

Gold's natural state has a definite shape and a definite volume. What is gold's natural state(s)?

zysi [14]

solid

Explanation:

because it has a definite shape and volume

8 0

3 years ago