No, she has it backward. Waves interfere with each other and reflect off objects. When two waves overlap their amplitudes add. If they have the same sign this addition is constructive, meaning the amplitudes grow. If they have opposite signs this constitutes subtraction and the waves can partially, or completely cancel. This is known as interference. Reflection occurs when waves travel from one medium to another. If the wave impedance of the new medium is different (which it generally is) there will be a partial, or even total, reflection.

7 0

3 years ago

Read 2 more answers

An 8.0 g bullet is fired from a gun at 120 m/s into a 2.0 kg block of wood sitting on a fence post. If the bullet hits the wood

nydimaria [60]

Answer:

$v = 0.478 m/s$

Explanation:

As we know that bullet strike the block and fix in it

so here if bullet and box is taken as a system then there is no external force on it

so here the initial momentum of bullet and block must be equal to final momentum of bullet and block

so here we have

$m_1v_{1i} + m_2v_{2i} = m_1v + m_2v$

now we have

$m_1 = 8 g$

$v_1 = 120 m/s$

$m_2 = 2kg$

$v_{2i} = 0$

now from above equation we have

$(0.008)(120) + 2(0) = (0.008)v + 2v$

$v = 0.478 m/s$

8 0

4 years ago

Which statement is true?

vivado [14]

Answer:

The speed of sound in air is not affected by the temperature

Explanation:

It just isn't™

4 0

3 years ago

Physics !!!!!!!!!!!!!!!!!

madreJ [45]

Answer:

1) v = -0.89 m/s

2) v = 36.5 m/s

Explanation:

1) Given

The mass of the boy, M = 45 Kg

The mass of the skateboard, m = 2 Kg

The initial velocity of the boy and skateboard is zero

According to the law of conservation of linear momentum

MV + mv = 0

V = - mv/M

Substituting the given values in the above equation

V = -2 x 20/ 45

= -0.89 m/s

Hence, the velocity of the boy, v = -0.89 m/s

2) Given

The mass of the boy, M = 47 Kg

The mass of the skateboard, m = 8 Kg

The initial combined velocity of the boy and skateboard, u = 4.2 m/s

The boy jumped off from the skateboard with velocity, V = -1.3 m/s

According to the law of conservation of momentum,

MV + mv = (M + m)u

v = [(M + m)u - MV] / m

Substituting the given values,

v = [(47 + 8)4.2 - 47(-1.3)] / 8

= 36.5 m/s

Hence, the velocity of the skateboard, v = 36.5 m/s

3 0

4 years ago