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3 years ago

When the sound of source is moving away from the observer the observer will hear a

Physics

2 answers:

hammer [34]3 years ago

6 0

a sound of lower fequency

NNADVOKAT [17]3 years ago

6 0

Sound of lower frequency waves

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A 1400 kg car is traveling east on the highway at 31 m/s and collides into the rear of a slower moving pickup truck of 2400 kg,

zloy xaker [14]

Answer: 31 m/s due east

Explanation: this question can be solved using the law of conservation of linear momentum.

This law states that in a closed or isolated system, during collision, the vector sum of momentum before collision equals the vector sum of momentum after collision.

Momentum = mass × velocity

From our question, our parameters before collision are given below as

Mass of car = mc = 1400kg

Speed of car =vc = 31 m/s (due east)

Mass of truck = mt = 2400kg

Velocity of truck = vt = 25 m/s ( due east )

After collision

Velocity of car = ?

Velocity of truck = 34 m/s ( due east )

Vector sum of momentum before collision is given as

1400 (31) + 2400 (25) = 43400 + 60000 = 103400 kgm/s

After collision the truck is seen to move faster (v = 34 m/s) which implies that the car also moves due east .

1400 (v) + 2400(25) .... A positive value is between both momenta because they are in the same direction.

After collision, we have that

1400v + 60000

Vector sum of momentum before collision = vector sum of momentum after collision

103400 = 1400v + 60000

103400 - 60000 = 1400v

43400 = 1400v

v = 43400/ 1400

v = 31 m/s due east

4 0

4 years ago

What are Earth's mineral resources and how long might reserves last?

amm1812

Reserves might last 53.3 years.

Earth’s mineral resources:

3 0

3 years ago

A ball that is attached to a string travels in a horizontal, circular path, as shown in Figure 1. At time t0 , the ball has a sp

Levart [38]

Answer:

F₁ = 4 F₀

Explanation:

The force applied on the string by the ball attached to it, while in circular motion will be equal to the centripetal force. Therefore, at time t₀, the force on ball F₀ is given as:

F₀ = mv₀²/r --------------- equation (1)

where,

F₀ = Force on string at t₀

m = mass of ball

v₀ = speed of ball at t₀

r = radius of circular path

Now, at time t₁:

v₁ = 2v₀

F₁ = mv₁²/r

F₁ = m(2v₀)²/r

F₁ = 4 mv₀²/r

using equation (1):

F₁ = 4 F₀

5 0

3 years ago

An automobile engine delivers 47.4 hp. how much time will it take for the engine to do 6.82 × 105 j of work? one horsepower is e

kogti [31]

1 horsepower is equal to 746 W, so the power of the engine is
$P=47.4 hp \cdot 746 \frac{W}{hp}=35360 W$
The power is also defined as the energy E per unit of time t:
$P= \frac{E}{t}$
Where the energy corresponds to the work done by the engine, which is $E=6.82 \cdot 10^5 J$ . Re-arranging the formula, we can calculate the time t needed to do this amount of work:
$t = \frac{E}{P}= \frac{6.82 \cdot 10^5 J}{35360 W}=19.3 s$

8 0

3 years ago

physical changes occur when existing bonds break and new bonds form

Luba_88 [7]

A physical change is any change that alters the form or appearance of a substance but does not change it into another substance
-Some of the physical properties may be altered, but the chemical composition stays the same
-Examples: Bending, Crushing, Cutting, Melting, Freezing, Boiling

6 0

3 years ago