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4 years ago

Which statement is correct?

Physics

1 answer:

NISA [10]4 years ago

5 0

Answer:

1st statement is true

Explanation:

Here statement 1 is correct

Let think about it, if you push down the bar then you are lifting your weight off the pedals.

Obviously, this question does not take into account of racing bikes with straps on pedals, where you would push on one side and pull on the other to match your legs are doing, with straps your other leg can pull pedals upward.

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Which of the following represents an upright image? <br> A. -do<br> B. +m<br> C. -m<br> D. +do

Tom [10]

Answer:

B. +m

Explanation:

The magnification of an image is defined as the ratio between the size of the image and of the object:

$m = \frac{y'}{y}$

where we have

y' = size of the image

y = size of the object

There are two possible situations:

- When m is positive, y' has same sign as y: this means that the image image is upright

- When m is negative, y' has opposite sign to y: this means that the image is upside down

Therefore, the correct option representing an upright image is

B. +m

5 0

3 years ago

The engine in an imaginary sports car can provide constant power to the wheels over a range of speeds from 0 to 70 miles per hou

kirill115 [55]

Answer:

Part A

it would take 6 sec

it would take 3 sec

Explanation:

We are told that the power supplied to the wheel is constant which means that the sport car is gaining energy i.e

$power \ \alpha \ energy$

Hence if power is constantly supplied energy constantly increase

From the formula of the Kinetic energy

$KE = \frac{1}{2} mv^2$

we can see that as the speed doubles from 29 mph to 58 mph the energy needed is $2^2$ = 4 times of the energy from the formula

Also the time needed would also be 4 times because energy i directly proportional to time

Hence to reach 58mph the time that it would take is

= $4* 1.5sec = 6sec$

We are told that the ground pushes the car with a constant force and

F = ma

this means that the acceleration is also constant

now from newtons law

v = u +at

Looking at it we see that final velocity is directly proportional with time

hence it would take twice the time to reach twice the final velocity

Time to reach 58mph = 3 s

since time to reach 29 mph( $\frac{1}{2} \ of \ [58mph]$ ) =( $\frac{1}{2} \ of \ 3sec$ )1.5 s

6 0

3 years ago

Measurements of how orbital speeds depend on distance from the center of our galaxy tell us that stars in the outskirts of the g

diamong [38]

Answer:

True

Explanation:

Measurements of how orbital speeds depend on distance from the center of our galaxy tell us that stars in the outskirts of the galaxy. True or False

stars in the outskirt orbit the galactic center

the object mean orbital speed depends only on the Earth's mass and the semi-major axis (half the longest diameter) of the object's orbit. worthy of note. the orbital speed changes depending on where in the orbit the object is. It will be greatest when closest to Earth and least when furthest from Earth.

5 0

3 years ago

What is the kinetic energy of the silver sphere at the moment it hits the ground? (Assume that energy is conserved during the fa

lesya [120]

Answer:

Kinetic Energy = 0

Explanation:

No matter if energy is totally conserved during the fall or when it hits the ground, the kinetic energy of the silver sphere will be zero because the velocity component in $K.E = 1/2mv^{2}$ becomes zero, the over all energy becomes zero.

4 0

3 years ago

Assuming barber wants to setup a saloon in a measuring length of 3m by 3m. He has a simple wooden chairs,3 large mirror and one

CaHeK987 [17]

The best way to arrange the salon to best use what he has is:

Place the bulb in the middle of the wall
Directly face the chair and mirror in front of the bulb for proper lighting and reflection
Place the chairs side by side of each other
Each mirror should be facing each chai

<h3>What is Reflection?</h3>

This refers to the change in direction of a wavefront between two different media so that the wavefront returns to its originating medium.

Hence, we can see that from our knowledge of shadows and reflection, we can note that mirrors reflect and light helps to bring detail in a dark area and the chairs should be facing the mirrors directly so the customer can see his hair and how it is being cut by the barber.