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3 years ago

In physics, what is the positive and negative sign used for when applied to velocity and acceleration?

Physics

1 answer:

Kobotan [32]3 years ago

6 0

Answer:

Opposite direction

Explanation:

For example: The first object travels in the direction pointing to east, while the other one travels pointing to the west.

The first object will have a positive value while the second one will have a negative, cause it's going to the opposite direction

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A student constructed a series circuit consisting of a 12.0-volt battery, a 10.0-ohm lamp, and a

Zolol [24]

Considering the unknown resistence as R and using the Ohm's First Law, we have:

$i= \frac{V}{R_{eq}} \\ 0.5= \frac{12}{R+10} \\ R+10=24 \\ R=14-Ohm$

The equivalent resistence is given by the resistor series with the lamp resistence.

$R_{eq}=R+10 \\ R_{eq}=14+10 \\ \boxed {R_{eq}=24-Ohm}$

If you notice any mistake in my english, please let me know, because i am not native.

6 0

3 years ago

when the cross product of vector A and B are 2i+3j+4k and the sum of vector A and B are 3i+8j+7k then what will be the two vecto

Kryger [21]

Explanation:

the two vectors are 5i+11j+11k

8 0

2 years ago

The Olympic record for a marathon is 2.00 hour 9.00 minute 21.0 seconds if the average speed of the runner achieving this record

iren2701 [21]

(2.00 hours) x (3,600 seconds/hour) = 7,200 seconds

(9.00 minutes) x (60 seconds/minute) = 540 seconds

The record time = (7,200 + 540 + 21) = 7,761 seconds

Distance = (speed) x (time)

= (5.436 m/s) x (7,761 sec) = 42,188.8 meters
________________________________________________

The official length of the marathon run is 42,195 meters.
If we divide that by the record time in the question, we get

5.4368... m/s .

Rounded to the nearest thousandth, that's 5.437 m/s.

If the question had given the speed as 5.437 instead of 5.436 ,
then we would have calculated the distance to be

(5.437 m/s) x (7,761 sec) = 42,196.6 meters,

4.6 meters closer to the official distance than the answer we did get.

3 0

3 years ago

A 50kg chandelier hangs from a ceiling suspended by a cable.

babunello [35]

Answer:

The tension force has a magnitude of 490 N, and acts vertically upward

Explanation:

The complete question is:

A 50kg chandelier hangs from a ceiling suspended by a cable. What is the Tension (magnitude and direction of the force) in the cable?

ANS:

Tension is the force applied axially by rope, chain, cable, rod, etc, as a reaction force. The direction of tension is always towards the support. Since, the support here, is ceiling.

Therefore, the direction of tension force will be vertically upward.

Since the chandelier is hanging stationary, without any motion. Thus, there must not be any unbalanced force applied on it.

Hence, the tension force must be equal to the weight of chandelier.

Tension Force = Weight of Chandelier

T = W = mg

T = (50 kg)(9.8 m/s²)

T = 490 N

Thus, the tension force has a magnitude of 490 N, and acts vertically upward

6 0

3 years ago

A football punter accelerates a football from rest to a speed of 15 m/s during the time in which his toe is in contact with the

ioda

Answer:

Force, F = 44 N

Explanation:

Given that,

Initial speed of the football, u = 0

Final speed, v = 15 m/s

The time of contact of the ball, t = 0.15 s

The mass of football, m = 0.44 kg

We need to find the average force exerted on the ball. It is given by the formula as :

$F=ma\\\\F=\dfrac{mv}{t}\\\\F=\dfrac{0.44\times 15}{0.15}\\\\F=44\ N$

So, the average force exerted on the ball is 44 N. Hence, this is the required solution.

6 0

3 years ago