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3 years ago

Given this graph plotting velocity versus time, estimate the acceleration of object A at points X and Y respectively.

Physics

2 answers:

Molodets [167]3 years ago

8 0

A. 0 meters/second2 and -1 meter/second2 for plato people

swat323 years ago

5 0

Point X lies on a horizontal line. We can intuitively say that the slope of the graph at point X is 0, therefore the acceleration at point X is 0m/s²

Point Y lies on a downward slanting line. To calculate the slope of that line, let's apply this equation:

m = (y₂-y₁)/(x₂-x₁)

m = slope, (x₁, y₁) and (x₂, y₂) correspond to the coordinates of the line's endpoints.

Given values:

(x₁, y₁) = (7, 5)

(x₂, y₂) = (12, 0)

Plug in and solve for m:

m = (0 - 5)/(12 - 7)

m = -1

The acceleration at point Y is -1m/s²

Choice A

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A 5.0 A current is set up in a circuit for 6.0 min by a rechargeable battery with a 6.0 V emf. By how much is the chemical energ

Andre45 [30]

Answer:

The chemical energy of the battery was reduced in 10800J

Explanation:

The first thing to take into account is that the stored energy in a battery is in Watts per second or Joules ( $W\cdot s=J$ ). It means that the battery provides a power for a certain time.

The idea is to know how much $W\cdot s$ has been consumed by the circuit.

The first step is to know the power that is consumed by the circuit. It is $P=V\cdot I$ . The problem says that the circuit consumes a current of 5.0A with a voltage of 6.0V. It means that the power consumed is:

$P=V\cdot I=(6.0V)\cdot (5.0A)=30W$

The previous value (30W) is the power that the circuit consumes.

Now, you must find the total amount of power that is consumed by the circuit in 6.0 minutes. You just have to multiply the power that the circuit consumed by the time it worked, it means, 6.0 minutes.

$energy=P\cdot t=(30W)\cdot (6.0min)=180W\cdot min$

You must convert the minutes unit to seconds. Remember that 1 minute has 60 seconds.

$energy=P\cdot t=(30W)\cdot (6.0min) \cdot \frac{60s}{1min}=10800W\cdot s=10800J$

Thus, the chemical energy of the battery was reduced in 10800J

8 0

4 years ago

A circuit contains a 1.5v battery and a bulb with a 3 ohms resistance, calculate the current of the circuit

Cerrena [4.2K]

Answer:

0.5A

Explanation:

V=IR where V is 1.5V, R is 3 ohms

Hence 1. 5= I x 3

1.5/3 =I

I =0.5 A

Current is 0. 5 amperes

5 0

3 years ago

Why sun is known as main or ultimate<br>source of energy?( please in short answer)

erastova [34]

Answer:

because of the heats came from to ultraviolet trnasform and i thankyou

6 0

3 years ago

A plastic film moves over two drums. During a 4-s interval the speed of the tape is increased uniformly from v0 = 2ft/s to v1 =

Ratling [72]

Answer:

Question 1)

a) The speed of the drums is increased from 2 ft/s to 4 ft/s in 4 s. From the below kinematic equations the acceleration of the drums can be determined.

$v_1 = v_0 + at \\4 = 2 + 4a\\a = 0.5~ft/s^2$

This is the linear acceleration of the drums. Since the tape does not slip on the drums, by the rule of rolling without slipping,

$v = \omega R\\a = \alpha R$

where α is the angular acceleration.

In order to continue this question, the radius of the drums should be given.

Let us denote the radius of the drums as R, the angular acceleration of drum B is

α = 0.5/R.

b) The distance travelled by the drums can be found by the following kinematics formula:

$v_1^2 = v_0^2 + 2ax\\4^2 = 2^2 + 2(0.5)x\\x = 12 ft$

One revolution is equal to the circumference of the drum. So, total number of revolutions is

$x / (2\pi R) = 6/(\pi R)$

Question 2)

a) In a rocket propulsion question, the acceleration of the rocket can be found by the following formula:

$a = \frac{dv}{dt} = -\frac{v_{fuel}}{m}\frac{dm}{dt} = -\frac{13000}{2600}25 = 125~ft/s^2$

b) $a = -\frac{v_{fuel}}{m}\frac{dm}{dt} = - \frac{13000}{400}25 = 812.5~ft/s^2$

5 0

4 years ago

A 2800 kg truck moving at 12 m/s to the right hits a stopped 1100 kg car. What is the combined velocity the moment they stick to

leva [86]

Answer:

The combined velocity is 8.61 m/s.

Explanation:

Given that,

The mass of a truck, m = 2800 kg

Initial speed of truck, u = 12 m/s

The mass of a car, m' = 1100 kg

Initial speed of the car, u' = 0

We need to find the combined velocity the moment they stick together. Let it is V. Using the conservation of momentum.

$m_1v_1+m_2v_2=(m_1+m_2)V\\\\V=\dfrac{m_1v_1+m_2v_2}{(m_1+m_2)}\\\\V=\dfrac{2800\times 12+0}{2800+1100}\\\\V=8.61\ m/s$

So, the combined velocity is 8.61 m/s.

5 0

3 years ago