PHYSICS MIDDLE SCHOOL

Which section of the graph represents negative acceleration?

Answers

Answer 1

Answer: The area between the 10 and the 12.

Answer 2

Answer: C, because it going down, which is negative and also it change in speed

C. 400 J

Explanation:

In physics, work is defined as

$W=F * \Delta d$

Where $W$ is the word done, $F$ is the force that move the object and $\Delta d$ is the change of the position of the object.

In this case, we have

$F= 100 \ N$

$\Delta d= 6m - 2m = 4m$ , remember that the difference refers to the actual subtraction between the final point and the initial point of the object.

Replacing these values, we have

$W= 100 \ N * 4m\nW=400 \ Joules$

Therefore, the right answer is C. The work done is 400 Joules

Answer:

400 J

Explanation:

I just took the test and can confirm this.

In DC motor, the split rings are made of
A) steel B) copper C) wood D) glass

Answers

Answer:

B)Copper

Explanation:

The DC motor is provided with some devices or the parts to periodically change the direction of the current in the motor. way as that of the armature rotation. The split rings are made up of the copper and the spindle connected to it is made of carbon.

$\bold \pink{ \underline{hope \: it \: helps}}$

Which is true about carbon-12 compared with carbon-13

Answers

e mass number of any given atom depends solely on the number of protons and neutrons in its nucleus. The mass number of any atom can be determined by adding the number of protons and neutrons. (Mathematically this is stated as Mass Number = Protons + Neutrons). For instance, a Carbon atom with 6 protons and 6 neutrons will have a mass number of 12AMU. However, a Carbon atom with 6 protons and 8 Neutrons will have a mass number of 14AMU. They are both Carbon atoms, however they each have a different mass number. Atoms of the same element that have different numbers of neutrons, and therefore, different mass numbers, are called isotopes. Isotopic symbols are used to indicate isotopes of the same elements. In the following isotopic symbols the lower number is the atomic number…it is the number of protons. The upper number is the mass number, it represents to sum of the protons and neutrons in the atoms nucleus.

A person with a mass of 15kg is walking uphill at a velocity of2m/s. What is the walker's momentum?

Answers

Answer:

30 kgm/s

Explanation:

The momentum of a body is given by the product of mass and its velocity.

∴ momentum = mv

= 15 × 2

= 30 kgm/s

A 60kg bicyclist (including the bicycle) is pedaling to theright, causing her speed to increase at a rate of 3.1 m/s2,
despite experiencing a 60N drag. Neglect any friction
impeding her motion.

How many forces are acting on the bicyclist?

What is the magnitude of the net force on the bicyclist?

How much force is the bicyclist generating through her
pedaling?

Answers

a) 4 forces

b) 186 N

c) 246 N

Explanation:

Let's count the forces acting on the bicylist:

1) Weight ( $W=mg$ ): this is the gravitational force exerted on the bicyclist by the Earth, which pulls the bicyclist towards the Earth's centre; so, this force acts downward (m = mass of the bicyclist, g = acceleration due to gravity)

2) Normal reaction (N): this is the reaction force exerted by the road on the bicyclist. This force acts vertically upward, and it balances the weight, so its magnitude is equal to the weight of the bicyclist, and its direction is opposite

3) Applied force ( $F_A$ ): this is the force exerted by the bicylicist to push the bike forward. Its direction is forward

4) Air drag ( $R$ ): this is the force exerted by the air on the bicyclist and resisting the motion of the bike; its direction is opposite to the motion of the bike, so it is in the backward direction

So, we have 4 forces in total.

Here we can find the net force on the bicyclist by using Newton's second law of motion, which states that the net force acting on a body is equal to the product between the mass of the body and its acceleration:

$F_(net)=ma$