Why capillary happen.

5. What is the frequency of a sound wave when the speed of the sound is 340 m/s and has a wavelength of 1.21 m?

LekaFEV [45]

Explanation:

v = f × /\

340 = 1.21f

f = 280.99Hz

3 0

3 years ago

Kelli weighs 425 N, and she is sitting on a playground swing that hangs 0.36 m above the ground. Her mom pulls the swing back an

kodGreya [7K]

Answer:

V = 3.54 m/s

Explanation:

Using the conservation of energy:

$E_i = E_f$

so:

$wh = \frac{1}{2}mV^2$

where w is te weigh of kelly, h the distance that kelly decends, m is the mass of kelly and V the velocity in the lowest position.

So, the mass of kelly is:

m = 425N/9.8 = 43.36 Kg

and h is:

h = 1m-0.36m =0.64m

then, replacing values, we get:

$(425N)(0.64m) = \frac{1}{2}(43.36kg)v^2$

Solving for v:

V = 3.54 m/s

7 0

3 years ago

A ball is launched with initial speed v from ground level up a frictionless slope (This means the ball slides up the slope witho

amid [387]

Answer:

hmax = 1/2 · v²/g

Explanation:

Hi there!

Due to the conservation of energy and since there is no dissipative force (like friction) all the kinetic energy (KE) of the ball has to be converted into gravitational potential energy (PE) when the ball comes to stop.

KE = PE

Where KE is the initial kinetic energy and PE is the final potential energy.

The kinetic energy of the ball is calculated as follows:

KE = 1/2 · m · v²

Where:

m = mass of the ball

v = velocity.

The potential energy is calculated as follows:

PE = m · g · h

Where:

m = mass of the ball.

g = acceleration due to gravity (known value: 9.81 m/s²).

h = height.

At the maximum height, the potential energy is equal to the initial kinetic energy because the energy is conserved, i.e, all the kinetic energy was converted into potential energy (there was no energy dissipation as heat because there was no friction). Then:

PE = KE

m · g · hmax = 1/2 · m · v²

Solving for hmax:

hmax = 1/2 · v² / g

4 0

4 years ago

The electric force between two charges A. increases with distance between the charges B. increases if either one of charges gets

beks73 [17]

Answer:

Option (A) , (b) and (d) are correct option

Explanation:

According to Coulomb's law electric force between two charges is given by

$F=\frac{1}{4\pi \epsilon _0}\frac{q_1q_2}{r^2}$

From the relation we can say that force is directly proportional to magnitude of charges and inversely proportional to distance between them '

So if we increase the distance then force will decrease

Increase if any of the charge get larger

If force is attractive then both the charge will be of different sign and is force is repulsive then both the charges of same sign

From above conclusion we can say that (a), (b) and (d) are correct option

6 0

3 years ago

A toy cannon launches a 46-g golf ball straight up into the air with a kinetic energy of 6.8 J. What must the

Shkiper50 [21]

Answer : The correct option is, (C) 17 m/s

Explanation :

Formula used :

$K.E=\frac{1}{2}mv^2$

where,

K.E = kinetic energy = 6.8 J

m = mass of object = 46 g = 0.046 kg (1 kg = 1000 g)

v = velocity

Now put all the given values in the above formula, we get:

$K.E=\frac{1}{2}mv^2$

$6.8J=\frac{1}{2}\times 0.046kg\times v^2$

$6.8kg.m^2/s^2=\frac{1}{2}\times 0.046kg\times v^2$

$v=17.19m/s\approx 17m/s$

Therefore, the ball's velocity be as it leaves the cannon is, 17 m/s

3 0

3 years ago