What is NOT an example of Reflection

A bullet is fired vertically into a 1.40 kg block of wood at rest directly above it. if the bullet has a mass of 29.0 g and a sp

larisa86 [58]

5.47 m
The bullet undergoes a non-elastic collision with the block of wood and momentum is conserved. The initial momentum is 0.029 kg * 510 m/s = 14.79 kg*m/s. The combined mass of the block and bullet is 1.40 kg * 0.029 kg = 1.429 kg. Since momentum is conserved, the velocity of both combined will then be 14.79 kg*m/s / 1.429 kg = 10.34989503 m/s.
With a local gravitational acceleration of 9.8 m/s^2, it will take 10.34989503 m/s / 9.8 m/s^2 = 1.056111738 s for their upward velocity to drop to 0, just prior to descending.
The equation for distance under constant acceleration is
d = 0.5 A T^2
so
d = 0.5 * 9.8 m/s^2 * (1.056111738 s)^2
d = 4.9 m/s^2 * 1.115372003 s^2
d = 5.465322814 m
Rounding to 3 significant figures gives a height of 5.47 meters.

6 0

3 years ago

How much heat is required to heat 0.1 g of ∆hvap =2260 j/g ∆h =340j/g fus iceat−30ctosteamat100c? use the approximate values?

Anestetic [448]

How much heat<span> is </span>required<span> to </span>heat 0.1 g<span> of </span>∆hvap<span> =</span>2260 j/g ∆h<span> =</span>340j/g fus iceat−30 ctosteamat 100c?use<span> the </span>approximate values<span>?</span>

7 0

3 years ago

A private aviation helicopter's main rotor blades rotate at approximately

Arisa [49]

Answer: 7.5 rev/s

Explanation:

We are given the angular velocity $\omega$ a helicopter's main rotor blades:

$\omega=450 rpm=450 \frac{rev}{min}$

However, we are asked to express this $\omega$ in the International Systrm (SI) units. In this sense, the SI unit for time is second ( $s$ ):

$\omega=450 \frac{rev}{min} \frac{1 min}{60 s}$

$\omega=7.5 \frac{rev}{s}$

4 0

3 years ago

A compound microscope is equipped with two objective lenses (10x and 45x) and has a 10x ocular lens. The highest magnification a

Wittaler [7]

Answer:

450X

Explanation:

When a specimen is been viewed, both

objective and ocular lenses works together so that the object is magnified.

From the question,objective lenses are;

1)10x

2)45x

ocular lens= 10x

Highest magnification

= 10X ocular × 45X objective

=450X

This implies that the image that was viewed will appear 450 times the actual size.

5 0

3 years ago

A brick of mass 5 kg is released from rest at a height of 3 m. How fast is it going when it hits the ground? Acceleration due to

sineoko [7]

Taking into account the definition of kinetic, potencial and mechanical energy, when the brick hits the ground, it has a speed of 7,668 m/s.

<h3>Kinetic energy</h3>

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and at rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.

The kinetic energy is represented by the following expression:

Ec= ½ mv²

Where:

Ec is the kinetic energy, which is measured in Joules (J).
m is the mass measured in kilograms (kg).
v is the speed measured in meters over seconds (m/s).

<h3>Potential energy</h3>

On the other hand, potential energy is the energy that measures the ability of a system to perform work based on its position. In other words, this is the energy that a body has at a certain height above the ground.

Gravitational potential energy is the energy associated with the gravitational force. This will depend on the relative height of an object to some reference point, the mass, and the force of gravity.

So for an object with mass m, at height h, the expression applied to the gravitational energy of the object is:

Ep= m×g×h

Where:

Ep is the potential energy in joules (J).
m is the mass in kilograms (kg).
h is the height in meters (m).
g is the acceleration of fall in m/s².

<h3>Mechanical energy</h3>

Finally, mechanical energy is that which a body or a system obtains as a result of the speed of its movement or its specific position, and which is capable of producing mechanical work. Then:

Potential energy + kinetic energy = total mechanical energy

<h3>Principle of conservation of mechanical energy </h3>

The principle of conservation of mechanical energy indicates that the mechanical energy of a body remains constant when all the forces acting on it are conservative (a force is conservative when the work it does on a body depends only on the initial and final points and not the path taken to get from one to the other.)

Therefore, if the potential energy decreases, the kinetic energy will increase. In the same way, if the kinetics decreases, the potential energy will increase.

A brick of mass 5 kg is released from rest at a height of 3 m. Then, at this height, the brick of mass has no speed, so the kinetic energy has a value of zero because it depends on the speed or moving bodies. But the potential energy is calculated as:

Ep= 5 kg× 9.8 $\frac{m}{s^{2} }$ × 3 m

Solving:

So, the mechanical energy is calculated as:

Potential energy + kinetic energy = total mechanical energy

147 J + 0 J= total mechanical energy

147 J= total mechanical energy

The principle of conservation of mechanical energy can be applied in this case. Then, when the brick hits the ground, the mechanical energy is 147 J. In this case, considering that the height is 0 m, the potential energy is zero because this energy depends on the relative height of the object. But the object has speed, so it will have kinetic energy. Then:

Potential energy + kinetic energy = total mechanical energy

0 J + kinetic energy= 147 J

kinetic energy= 147 J

Considering the definition of kinetic energy:

½ 5 kg×v²= 147 J

$v=\sqrt{\frac{2x147 J}{5 kg} }$