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2 years ago

I'm not quite sure how the formula works. I thought it was

Physics

1 answer:

juin [17]2 years ago

4 0

Answer:

See the explanation below.

Explanation:

Of course yes, after my explanation you will understand very well how to analyze this type of problems.

First, we must differentiate the weight of the mass, the mass has units of kilograms or pounds, while the weight is the product of the mass by gravitational acceleration. In this way, we have the following formula for the weight of anybody.

w = m*g

where:

w = weight [N] (units of Newtons]

m = mass [kg]

g = gravity acceleration = 9.81 [m/s²]

When we have the product of these units [kg]*[m/s²], We are always going to get as a result the units of Newtons [N], The Newton is a unit of force.

Now, to solve this problem we must use Newton's second law, which tells us that the sum of forces on a body must be equal to the product of mass by acceleration.

ΣF = m*a

where:

ΣF = forces acting over the gymnast [N]

m = mass = 55 [kg]

a = desacceleration = 6*9.81 = 58.86 [m/²]

Now we have two forces acting over the gymnast the first one is his or her weight (the mass by the gravity acceleration) and the second force is the one made it by his or her legs upwards in order to be standing. Let's take as positive signs the movements and forces upwards and negative downwards

- (m*g) + Fl = m*a

where:

Fl = force made it by the legs [N]

As the deceleration is upward because it prevents the person from continuing to go down, it is taken as a positive sign.

- (55*9.81) + Fl = (55*58.86)

Fl = (55*58.86) + (55*9.81)

Fl = 3776.85 [N]

I hope you can understand :)

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A 2 kg ball is moving 3 m/s when it starts rolling up a hill.

AURORKA [14]

Answer:

the height reached is = 0.458 [m]

Explanation:

We need to make a sketch of the ball and see the location of the reference point where the potential energy is zero. But the kinetic energy will be defined by the following expression:

$Ek=\frac{1}{2} *m*v^{2} \\where:Ek= kinetic energy [J]\\m = mass of the ball [kg]\\v = velocity of the ball [m/s]$

Replacing the values on the equation we have:

$Ek=\frac{1}{2}*(2)*(3^{2} )\\ Ek=9[J]\\$

This kinetic energy will be transformed in potential energy in the moment when the ball starts to rolling up. Therefore the maximum height reached by the ball depends of the initial velocity given to the ball.

$Ek=Ep\\where\\Ep=potential energy [J]\\Ep=m*g*h\\where\\g=gravity = 9.81[m/s^2]\\h=height reached [m]\\$

Now we have:

$h=\frac{Ep}{m*g} \\h=\frac{9}{2*9.81} \\\\h=0.45 [m]$

In that moment when the ball reach the 0.45 [m] the potencial energy will be maximum and equal to the kinetic energy when the ball has a velocity of 3[m/s]

6 0

3 years ago

A common physics demonstration is to drop a small magnet down a long, vertical aluminum pipe. Describe the motion of the magnet

Rzqust [24]

Answer and Explanation:

This experiment is known as Lenz's tube.

The Lenz tube is an experiment that shows how you can brake a magnetic dipole that goes down a tube that conducts electric current. The magnet, when falling, along with its magnetic field, will generate variations in the magnetic field flux within the tube. These variations create an emf induced according to Faraday's Law:

$\varepsilon =-\frac{d\phi_B}{dt}$

This emf induced on the surface of the tube generates a current within it according to Ohm's Law:

$V=IR$

This emf and current oppose the flux change, therefore a field will be produced in such a direction that the magnet is repelled from below and is attracted from above. The magnitude of the flux at the bottom of the magnet increases from the point of view of the tube, and at the top it decreases. Therefore, two "magnets" are generated under and above the dipole, which repel it below and attract above. Finally, the dipole feels a force in the opposite direction to the direction of fall, therefore it falls with less speed.

7 0

3 years ago

Read 2 more answers

To calibrate the calorimeter electrically, a constant voltage of 3.6 V is applied and a current of 2.6 A flows for a period of 3

iren [92.7K]

Answer:

$372.3 J/^{\circ}C$

Explanation:

First of all, we need to calculate the total energy supplied to the calorimeter.

We know that:

V = 3.6 V is the voltage applied

I = 2.6 A is the current

So, the power delivered is

$P=VI=(3.6)(2.6)=9.36 W$

Then, this power is delivered for a time of

t = 350 s

Therefore, the energy supplied is

$E=Pt=(9.36)(350)=3276 J$

Finally, the change in temperature of an object is related to the energy supplied by

$E=C\Delta T$

where in this problem:

E = 3276 J is the energy supplied

C is the heat capacity of the object

$\Delta T =29.1^{\circ}-20.3^{\circ}=8.8^{\circ}C$ is the change in temperature

Solving for C, we find:

$C=\frac{E}{\Delta T}=\frac{3276}{8.8}=372.3 J/^{\circ}C$

5 0

2 years ago

Which of these is the unit of measure for work?

ryzh [129]

The unit of measurement of work is the Joules. B.

4 0

3 years ago

NEED ANSWERED ASAP!! will give brainliest!

kotegsom [21]

The kinetic energy of any moving object is

K.E. = (1/2) (mass) (speed)² .

To use this simple formula, the 'mass' has to be in kilograms,
and the 'speed' has to be in meters-per-second.

You can see that we have a slight problem that has to be cleaned up:
The speed in the question is given in "kilometers per hour", but we'll
need it in "meters per second". So let's convert that right now:

(600 km/hour) x (1 hour / 3600 seconds) x (1000 meters / km)

= (600 x 1 x 1000 / 3600) (km-hour-meters / hour-second-km)

= 166.67 meters/second .

Now we're ready to plug numbers into the formula for K.E.

(1/2) (mass) (speed)²

= (1/2) (80,000 kg) (166.67 m/s)²

= (40,000 kg) (27,777.8 m²/s²)

= 1,111,111,111 kg-m²/s²

= 1.1... x 10⁹ Joules (choice D)

8 0

3 years ago