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3 years ago

An object has a mass of 5 kg. What force is needed to accelerate it at 6 m/s2? (Formula: F=ma)

Physics

2 answers:

Studentka2010 [4]3 years ago

5 0

Force needed is 5×6=30

stich3 [128]3 years ago

4 0

Answer:

Explanation:

According to Newton's second law, a force applied to certain object will accelerate it, that's the meaning of the formula: $F= ma$

So, in this case, we don't have to analyse much, because all values are given, we just have to replace them and solve for F:

$F=ma\\F=5kg(6m/s^{2})=30N$

Therefore, the force needed to accelerate that mass is 30 N.

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What is the radius of a tightly wound solenoid of circular cross-section that has 180turns if a change in its internal magnetic

Nata [24]

Answer:

Radius of cross section, r = 0.24 m

Explanation:

It is given that,

Number of turns, N = 180

Change in magnetic field, $\dfrac{dB}{dt}=3\ T/s$

Current, I = 6 A

Resistance of the solenoid, R = 17 ohms

We need to find the radius of the solenoid (r). We know that emf is given by :

$E=N\dfrac{d\phi}{dt}$

$E=N\dfrac{d(BA)}{dt}$

Since, E = IR

$IR=NA\dfrac{dB}{dt}$

$A=\dfrac{IR}{N.\dfrac{dB}{dt}}$

$A=\dfrac{6\ A\times 17\ \Omega}{180\times 3\ T/s}$

$A=0.188\ m^2$

$A=0.19\ m^2$

Area of circular cross section is, $A=\pi r^2$

$r=\sqrt{\dfrac{A}{\pi}}$

$r=\sqrt{\dfrac{0.19}{\pi}}$

r = 0.24 m

So, the radius of a tightly wound solenoid of circular cross-section is 0.24 meters. Hence, this is the required solution.

5 0

3 years ago

Un ala de aluminio en un avión de pasajeros es

Lesechka [4]

Answer:

No lo sé

Explanation:

7 0

3 years ago

NEED HELP !!!!!

goblinko [34]

Answers with Explanations:

1. Answer: True

Explanation:

Muscle cramps happen especially during an "intense workout." The frequency of cramps is related to heat, thus it is important to stay hydrated all throughout the workout. Eating should be done at least 2 to 3 hours prior to workout because eating immediately before exercise leads to undigested food. Such kind of food causes cramps.

2. Answer: True

Explanation: Applying direct pressure immediately after the injury can help decrease bleeding. Blood loss results to blood that is collected under the skin. This turns into the color of blue or black, also known as "bruise." Decrease bleeding would then mean decrease bruising.

Applying pressure also decreases swelling because it restricts the blood flow and fluid from reaching into the injury.

3. Answer: False

Explanation: "Lordosis" refers to the body's natural lordotic curve. This is considered "normal." The excessive inward curve of the lumbar spine is called "hyperlordosis." This is commonly caused by poor posture, lack of exercise, obesity and spinal conditions.

4. Answer: False

Explanation: The mnemonic acronym "RICE" stands for Rest, Ice, Compression (not Cold) and Elevation. This term is commonly used in First Aid and was introduced by Gabe Mirkin in 1978.

5. Answer: True

Explanation: Keeping the proper posture during exercise prevents the body from encountering injuries. It also ensures that the body is executing the exercise by using the muscles properly.

6. Answer: False

Explanation: "Ice" is important in decreasing the swelling of the injury. It constricts the blood vessels which prevents the flow of blood and other fluids towards the site of injury.

7. Answer: False

Explanation: The spine is naturally straight if a person doesn't have a medical problem. However, scoliosis is a medical problem. It is a condition wherein a person's spine is curved, rather than being straight.

8. Answer: True

Explanation: When it comes to exercise, starting slow is the main key. It is followed by gradual building up. The increase will depend on the person's stamina. For example, starting with a warm-up, followed by a slow walk then pacing up to a brisk walk.

9. Answer: True

Explanation: Kyphosis is a spinal condition wherein the person's spine is excessively curved outward. This causes the upper back and the shoulders to be rounded. This condition is commonly called "hunchback."

10. Answer: True

Explanation: Proper posture entails the right amount of spinal curve. This means that the spine is in "neutral position." This means that the spine takes on the "S-shape." A little amount of curve results to a "flat back" while too much curve results to a "swayback."

11. Answer: all of the above

Explanation: Body posture and technique are important especially when it comes to exercise. Poor posture and technique lead to strain on joints, ligaments and injury especially to the muscles. This also puts the body out of alignment.

12. Answer: True

Explanation: Stretching is appropriately done at the end of a warm-up when the temperature has increased because at this time, the muscles are already flexible. It allows the muscles to be loosened and also aids in better performance during workouts or exercises.

13. Answer: False

Explanation: "Lifting" with your back only will result to muscle injury. There are several ways to do lifting such as "pull-ups" or "lat pull downs." This means that you are not lifting with your back only but using your other joints and muscles for lifting.

14. Answer: True

Explanation: "Warming-up" is an essential preparation before any workout because it prepares the body by increasing temperature and blood flow to the muscles. Without it, the muscles will become sore and the chance for injuries increases.

15. Answer: True

Explanation: "Cool down" is considered equally important as "warm-up." It lowers the body's temperature and lowers the amount of lactic acid that causes muscle cramping, soreness and stiffness.

16. Answer: True

Explanation: It is said that most people forget about warming up and cooling down before and after they work out. It is necessary to have 5 to 10 minutes of warm-up and cool down for every exercise routine.

17. Answer: False

Explanation: Knee extension is best done at 90 degrees angle as advised by most health experts. However, it depends on your capability and your exercise goals. For some people, extending beyond 90 degrees is beneficial.

18. Answer: True

Explanation: Tucking your belly button helps with your body's core exercise. If this is going to be done throughout the day, then surely it will strengthen the muscles. This can be done while a person is sitting down or walking.

4 0

3 years ago

A rifle that shoots bullets at 477 m/s is to be aimed at a target 45.5 m away. If the center of the target is level with the rif

Free_Kalibri [48]

Answer:

The rifle barrel must be pointed at a height of 4.45cm above the target so that the bullet hits dead center.

Explanation:

First, we need to sketch the situation so we can have a better idea of what the problem looks like (Refer to uploaded picture).

So as you may see in the drawing, when pointing the rifle to the target, we can see it as a triangle, but in reality, the bullet will have a parabolic trajectory. Both points of view will help us determine what the height must be. In order to find it, we need to first determine at what angle the bullet should be shot. In order to do so we can use the range formula, which looks like this:

$R=\frac{v^{2}sin(2\theta)}{g}$

Where R is the range of the bullet (this is how far it goes before it has the

same height it was shot from), v is the original speed of the bullet, θ is the angle at which the bullet is shot and g is the acceleration of gravity.

We can solve this equation for theta, so we get:

$gR=v^{2}sin(2\theta)$

$\frac{gR}{v^{2}}=sin(2\theta)$

$sin^{-1}(\frac{gR}{v^{2}})=2\theta$

$\theta=\frac{sin^{-1}(\frac{gR}{v^{2}})}{2}$

so now we can substitute the given data:

$\theta=\frac{sin^{-1}(\frac{(9.8m/s^{2})(45.5m)}{(477m/s)^{2}})}{2}$

so we get:

θ=0.05614°

once we get the angle, we can look at the triangle diagram. From the drawing we can see that we can use the tan function to find the height:

$tan \theta = \frac{h}{45.5m}$

so we can solve this for h, so we get:

$h=45.5m*tan(0.05614^{o})$

which yields:

$h=0.0445m$

$h=4.45cm$

5 0

3 years ago

If two measurements are very close to each other, then they are ____.

dimaraw [331]

I'd say b, precise, here.
If there's an error somewhere in the experiment or project, then it is consistently .... wrong. So, just 'cos you measure something precisely, it doesn't mean that you've measured it accurately. Maybe an example would be a measurement of length. If you used a metal ruler at zero degrees C, you can measure to say half a millimetre. A series of measurements of the same object would give very similar readings. But, if you used same metal ruler at, say 100 celsius (implausible) then you'd probably get a different set of readings. 'cos of the expansion of the metal ruler.

4 0

3 years ago

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