Find the velocity of a runner who has a mass of 75 kg and 3,700 Joules of energy.

Den pushes a desk 400 cm across the floor. He exerts a force of 10 N for 8 s to move the desk.

stellarik [79]

Answer: The correct option is Option b.

Explanation:

Power is defined as the rate of work done by an object.

Mathematically,

$P=\frac{W}{t}$ .....(1)

And work done is the product of force exerted on the object times the displacement covered by that object.

Mathematically,

$W=F.s$

Putting this value in above equation, we get:

$P=\frac{F.s}{t}$

where,

P = power = ?W

F = Force exerted = 10N

s = Displacement = 400cm = 4m (Conversion factor: 1m = 100 cm)

t = Time taken = 8s

Putting values in above equation, we get

$P=\frac{10\times 4}{8}\\\\P=5W$

Hence, the correct option is Option b.

7 0

3 years ago

Read 2 more answers

1. What is the name given to the total possibility of sound frequencies

exis [7]

Explanation:

1. The entire span of possible sound waves is called the acoustic spectrum. It is subdivided into infrasonic sounds, audible sounds, and ultrasonic sounds.

2. The difference between a musical note and another note at twice the frequency is called an octave.

3. Sound intensity varies with the inverse square of distance.

4 0

2 years ago

Assuming that each of the following objects is a typical example of its class, rank them by increasing density.

inysia [295]

molecular cloud <interstellar cloud <1 Msun protostar <1 Msun star <intercloud gas

Explanation:

Molecular cloud- They are a variety of interstellar cloud in which molecular hydrogen can sustain themselves. They have a very low temperature ranging from -440 to -370 degrees Fahrenheit or between 10 to 50 Kelvin. Owing to their extremely low temperature, they appear mostly dark when viewed through telescopes.

Interstellar cloud- They are a congregation of a large number of interstellar gases, dust and plasma in any galaxy or universe. They have varying temperature depending on their proximity to a star. E.g. Neutral hydrogen atom clouds have a temperature of around just 100 Kelvin while those in the near vicinity of a star have temperatures as high as 10,000 Kelvin.

1 Msun star- These stars have temperature anywhere between 5300 and 6000 Kelvin. The main source of such high surface temperature is nuclear fusion process where elemental hydrogen molecules are fused to form helium molecules.

1 Msun protostar- protostar is rather a young star which is still in formation phase (i.e. gathering mass from the parent molecular cloud). They have temperature anywhere between 2000-3000 kelvin and are accompanied by dust usually.

Intercloud gas- These are the remainder gases that are spread throughout the interstellar space. This Intercloud gas is divided into warm intercloud medium and extremely hot coronal gas with temperatures comparing to Sun’s corona. Warm intercloud forms the dominant part of intercloud gas with a temperature around 8000 Kelvin.

8 0

3 years ago

two horses are pulling a 325 kg wagon, initially at rest. The horses exert 250 N and 178 N forward forces, respectively. Ignorin

Dovator [93]

Answer:

AFter 3.5 s, the wagon is moving at: $4.62\,\,\frac{m}{s}$

Explanation:

Let's start by finding first the net force on the wagon, and from there the wagon's acceleration (using Newton's 2nd Law):

Net force = 250 N + 178 N = 428 N

Therefore, the acceleration from Newton's 2nd Law is:

$F=m\,*\,a\\a = \frac{F}{m} \\a= \frac{428}{325}\, \frac{m}{s^2} \\a\approx 1.32 \,\,\frac{m}{s^2}$

So now we apply this acceleration to the kinematic expression for velocity in an object moving under constant acceleration:

$v_f=v_i+a\,*\,t\\v_f=0+1.32\,*\,3.5\,\,\frac{m}{s} \\v_f=4.62\,\,\frac{m}{s}$

7 0

3 years ago

Which force has an infinite range and is always attractive

leva [86]

Answer:

Gravitational Force.

Explanation:

Being one of the fundamental forces of nature, gravitational force is the weakest but has an infinite range. It is always attractive and acts between any two pieces of matter in nature.

5 0

3 years ago