Select the words that make the sentence a true statement.

The impulse given to a ball with mass of 2 kg is 16 N*s. If the ball starts from rest, what is its final velocity?

Alik [6]

The impulse is equal to the variation of momentum of the object:
$I=\Delta p = m \Delta v$
where m is the mass object and $\Delta v = v_f - v_i$ is the variation of velocity of the object.

The ball starts from rest so its initial velocity is zero: $v_i=0$ . So we can rewrite the formula as
$I=m v_f$
or
$v_f = \frac{I}{m}$

and since we know the impulse given to the ball (I=16 Ns) and its mass (m=2 kg), we can find the final velocity of the ball:
$v_f = \frac{16 Ns}{2 kg}= 8 m/s$

7 0

3 years ago

Read 2 more answers

A long, thin solenoid has 390 turns per meter and a radius of 1.20 cm. The current in the solenoid is increasing at a uniform ra

gtnhenbr [62]

To solve this problem it is necessary to apply the concepts related to Faraday's law and the induced emf.

By definition the induced electromotive force is defined as

$\int E dl = -\frac{d\phi}{dt}$

$\int E dl = -(\frac{dB}{dt})A$

Where,

$\phi =$ Electric field

B = Magnetic Field

A = Area

At the theory the magnetic field is defined as,

$B = \mu_0 NI$

Where,

N = Number of loops

I = current

$\mu_0 =$ Permeability constant

We know also that the cross sectional area, is the area from a circle, and the length is equal to the perimeter then

A = \pi r^2

l = 2\pi r

Replacing at the previous equation we have that

$E (2\pi r) = \mu_0 n (\frac{di}{dt})(\pi R^2)$

Where,

R = Radius of the solenoid

r = The distance from the axis

Re-arrange to find the current in function of time,

$\frac{di}{dt} = \frac{Er}{\mu_0 NR^2}$

Replacing our values we have

$\frac{di}{dt} = \frac{(8.00*10^{-6})(0.0348)}{(4\pi*10^{-7})(390)(1.2*10^-2)^2}$

$\frac{di}{dt} = 3.94487A/s$

8 0

3 years ago

If you pour hot soup into a bowl, and the bowl stays cool to the touch, you can assume that...

sveta [45]

Answer:

The soup still is cool, or since its recent it will take a while to get warmer

Explanation:

3 0

3 years ago

A 7450 kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.35 m/s2 and feels no appreci

bagirrra123 [75]

Answer:

a) 520m

b) 10.30 s

c) 100,95 m/s

Explanation:

a) According the given information, the rocket suddenly stops when it reach the height of 520m, because the engines fail, and then it begins the free fall.

This means the maximum height this rocket reached before falling was 520 m.

b) As we are dealing with constant acceleration (due gravity) $g=9.8 \frac{m}{s^{2}}$ we can use the following formula:

$y=y_{o}+V_{o} t-\frac{gt^{2}}{2}$ (1)

Where:

$y_{o}=520 m$ is the initial height of the rocket (at the exact moment in which it stops due engines fail)

$y=0$ is the final height of the rocket (when it finally hits the launch pad)

$V_{o}=0$ is the initial velocity of the rocket (at the exact moment in which it stops the velocity is zero and then it begins to fall)

$g=9.8m/s^{2}$ is the acceleration due gravity

$t$ is the time it takes to the rocket to hit the launch pad

Clearing $t$ :

$0=520 m+0-\frac{9.8m/s^{2} t^{2}}{2}$ (2)

$t^{2}=\frac{-520 m}{-4.9 m/s^{2}}$ (3)

$t=\sqrt{106.12 s^{2}$ (4)

$t=10.30 s$ (5) This is the time

c) Now we need to find the final velocity $V_{f}$ for this rocket, and the following equation will be perfect to find it:

$V_{f}=V_{o}-gt$ (6)

$V_{f}=0-(9.8 m/s^{2})(10.30 s)$ (7)

$V_{f}=-100.95 m/s$ (8) This is the final velocity of the rocket. Note the negative sign indicates its direction is downwards (to the launch pad)

7 0

3 years ago

A bicycle is traveling with a speed of 12 m/s. The cyclist hits the brakes reducing the speed to 4 m/s in a time of 4.8 seconds.

Annette [7]

So, the acceleration of the bicycle is approximately <u>-1.67 m/s²</u> or it can be said to be decelerating approximately <u>1.67 m/s²</u>.

<h3>Introduction</h3>

Hi ! Here I will help material about linear motion changes regularly, which is where you will hear a lot of the term acceleration. Acceleration occurs when an object's speed increases in a certain time interval. Acceleration can be negative which is called deceleration. The relationship between acceleration with velocity and time is manifested in the equation:

$\boxed{\sf{\bold{a = \frac{v_2 - v_1}{t}}}}$