You move a box 5 meters and perform 900 joules of work. How much force did you apply to the box?

Someone who wants to sell you a Superball claims that it will bounce to a height greater than the height from which it is droppe

sergeinik [125]

Answer:

No

Explanation:

Unless there are other external forces, this will never be true. Because according to energy conservation, potential energy will be converted to kinetic energy as the ball falls down (so it loses height and gain speed). And vice versa, kinetic to potential when it bounces back. So the potential energy after must be the same (or smaller if losing heat to external environment), so it can only get the the same height or less, but not more.

7 0

2 years ago

The velocity of a 3.00 kg parti- cle is given by :v = (8.00tiˆ + 3.00t2jˆ) m/s, with time t in seconds. At the instant the net f

FromTheMoon [43]

Answer:

Part a)

Direction of net force is

$\theta = 46.7 degree$

Part b)

Direction of the velocity is given as

$\phi = 27.9 degree$

Explanation:

As we know that the velocity of the particle is given as

$v = 8.00 t \hat i + 3.00 t^2\hat j$

now the acceleration is given as

$a = \frac{dv}{dt}$

$a = 8.00 \hat i + 6.00 t\hat j$

now magnitude of net acceleration is given as

$a = \sqrt{64 + 36t^2}$

$F = 3a$

$35 = 3\sqrt{64 + 36t^2}$

$t = 1.41 s$

Part a)

Now direction of net force is given as

$tan\theta = \frac{F_y}{F_x}$

$tan\theta = \frac{6t}{8}$

$tan\theta = \frac{6(1.41)}{8}$

$\theta = 46.7 degree$

Part b)

Direction of the velocity is given as

$tan\phi = \frac{v_y}{v_x}$

$tan\phi = \frac{3.00 t^2}{8.00 t}$

$tan\phi = \frac{3.00(1.41)}{8.00}$

$\phi = 27.9 degree$

8 0

2 years ago

When Royce was 10 years old, he had a mass of

coldgirl [10]

Answer:

<em>The gravitational force between Royce and Earth would be doubled at 16 years.</em>

Explanation:

<em>"Newton's law of universal gravitation states that gravitation force between two masses is proportional to the magnitude of their masses and inverse-squared of their distance".</em>

Royce Scenario

At the age of 10 Royce's mass = 30kg

At the age of 16 Royce's mass = 60kg

From Newton's law of universal gravitation, an Increase in the mass of a body would amount to a corresponding increase in the gravitational force.

In the case of Royce, the mass double between the age of 10 and 16, so there would be an increase of the gravitation force by double.

6 0

2 years ago

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10-10 w/m2 . what is the

satela [25.4K]

The intensity is defined as the ratio between the power emitted by the source and the area through which the power is calculated:
$I= \frac{P}{A}$ (1)
where
P is the power
A is the area

In our problem, the intensity is $I=6.0 \cdot 10^{-10} W/m^2$ . At a distance of r=6.0 m from the source, the area intercepted by the radiation (which propagates in all directions) is equal to the area of a sphere of radius r, so:
$A=4 \pi r^2 = 4 \pi (6.0 m)^2 = 452.2 m^2$

And so if we re-arrange (1) we find the power emitted by the source:
$P=IA = (6.0 \cdot 10^{-10}W/m^2)(452.2 m^2)=2.7 \cdot 10^{-7} W$

3 0

2 years ago

3. A 75kg man sits at one end of a uniform seesaw pivoted at its center, and his 24kg son sits at the

bulgar [2K]

Answer:

The wife have to sit at 0.46 L from the middle point of the seesaw.

Explanation:

We need to make a sketch of the seesaw and the loads acting over it.

And by the studying of the Newton's law we can find the equation useful to find the distance of the mother sitting on the seesaw with respect to the center ot the pivot point.

A logical intuition will give us the idea that the mother will be on the side of her son to make the balance.

The maximum momentum with respect to the pivot point (0) will be:

$M=75 *\frac{L}{2}$

Where L/2 is the half of the distance of the seesaw

Therefore the other loads ( mom + son) must be create a momentum equal to the maximum momentum.

7 0

2 years ago