Which characteristics can be used to differentiate star systems? Select three options.

As a pelican flies through the air, it flaps its wings, thereby pushing down on the air below. What is the reaction force?

madam [21]

Answer:

the reaction force in this situation would be B

Explanation:

The action is the wings pushing down whilst the reaction is the air pushing up which allow the bird to fly .

plz mark brainliest to help me lvl up :P

7 0

3 years ago

Read 2 more answers

Physical fitness is related to our ability to carry out daily tasks without being too tired or sore. Please select the best answ

WARRIOR [948]

Physical fitness is related to our ability to carry out daily tasks without being too tired or sore. This statement is TRUE.

<h3>Further explanation </h3>

Good physical fitness means that you can perform daily activities, occupations, and sports. This condition will be achieved through good nutrition, regular exercise, and have enough rest.

The benefit of physical activity and exercise can be immediate as well as long-term. Most importantly, regular activity can improve your quality of life.There are four types of physical fitness:

Cardiovascular exercise: exercises that increase the work of the heart and lungs, such as walking, jogging, step aerobics, swimming, and biking. Cardio activity improves your heart/lung function and muscle mass.
Muscular strength exercise: this exercise is to build overall strength and muscle mass.
Joint flexibility exercise: this exercise to help the ability of the muscle group can be stretched or joint can be moved, for example: bending, lifting and driving. Stretching can reduce the risk of injury.
Muscular endurance exercise: this exercise to find out how many repetitions of exercises a person can perform, such as push-ups and sit-ups.

<h3>Learn more </h3>

Physical activity brainly.com/question/1400373

Environment factors that affecting physical fitness brainly.com/question/982205

Factors that influence physical fitness brainly.com/question/1488529

Keywords: physical fitness, the definition of physical fitness, physical activity

7 0

4 years ago

Read 2 more answers

Some people wish that we lived in a recollapsing universe that would eventually stop expanding and start contracting. For this t

Monica [59]

Answer:

(B) Dark energy does not exist and there is much more matter than current evidence suggests.

Explanation:

The repulsive force which is accelerating expansion of the universe is called as dark energy. Most of matter present in the universe is the dark matter of about eighty five percent.

So, a collapsing universe would not have the dark energy and there is more matter which is not the dark matter. This theory is rejected because expansion of the universe is observable.

4 0

4 years ago

||||| A 1.5 kg block and a 2.5 kg block are attached to opposite ends of a light rope. The rope hangs over a solid, frictionless

amid [387]

Answer

The lighter block will have the Positive Acceleration that is +2.45 m/s square.

A (1.5 Kg) = + 2.45 m/s square

Explanation:

To solve this there is a hard way to do this and there is an easy way to do this. The hard way is to solve Newton's second law for each block individually and then combine them and you get two equations with two unknowns. you try your best to solve the algebra without losing any sins but lets be honest it usually goes wrong.

So the easy way to do this the way to get the magnitude of the acceleration of the blocks. That is to say that i want to know the magnitude at which 2.5 Kg block accelerates or 1.5 Kg block accelerates when the the blocks were released.

Take the net external force that tries to make system go and divide it by total mass of the the system.

A (of System) = F(net external force) / m (total mass of system)

This is the quick way to know the magnitude of acceleration of the objects in the system. But this is only possible if the system is moved in same magnitude of acceleration that is 2.5 Kg block will move downward and 1.5 Kg block will move upward with the same magnitude. So here in this case we have friction-less pulley and the blocks will move with the same magnitude of acceleration.

To find the external forces

External forces are the forces which exerted on the objects in our system from the objects outside of our system. So one external force is the force of gravity. Both 2.5 Kg block and the force of gravity will be in downward direction.

Force of gravity on 2.5 Kg block

F = + (2.5 x 9.8) = 24.5

After releasing the rope the 2.5 Kg block will drive the system and accelerates in downward direction so It will be a positive force.

Force of gravity on 1.5 Kg block

F = - (1.5 x 9.8) = 14.7

The force of gravity on 1.5 Kg block will be negative because it will accelerate in upward or opposite direction of the force of gravity. Because the whole system is moving in one direction but the force of gravity on 1.5 Kg block is opposing the acceleration of the system.

Now divide the the Net external forces by total mass of the blocks that is

A (of System) = F(net external force) / m (total mass of system)

A = (+ 24.5 - 14.7) / 2.5 + 1.5

A = 9.8 / 4

A = 2.45 meter per second square

So the Acceleration of 2.5 Kg block will be Negative that is -2.45 m/s square. Since block is accelerating down and we usually treat down as negative.

A (1.5 Kg) = - 2.45 m/s square

So the Acceleration of 1.5 Kg block will be Positive that is +2.45 m/s square. Since block is accelerating up and we usually treat up as positive.

A (1.5 Kg) = + 2.45 m/s square

4 0

4 years ago

Help

elena55 [62]

Answer:

I took the test, and the correct answer is not Hydrosphere and Geosphere, but instead, its actually Hydrosphere and Atmosphere

Explanation:

4 0

3 years ago