Which<br> factors will increase the speed of a sound wave in the air?

A 2 kg blob of sticky putty is thrown with a velocity of 5 m/s at a 1 kg doll. After impact, the putty sticks to the doll and co

kow [346]

Answer:3.33 m/s

Explanation:

Given

mass of Putty M=2 kg

the velocity of bob u=5 m/s

mass of doll m=1 kg

As there is no external force acting so linear momentum is conserved

Mu=(M+m)v

where v=common velocity of putty and doll after the impact

$2\times 5=(2+1)v\\v=\dfrac{10}{3}\ m/s\approx3.33\ m/s$

6 0

3 years ago

If, instead, the ball is revolved so that its speed is 3.7 m/s, what angle does the cord make with the vertical?

Delicious77 [7]

Complete Question:

A 0.50-kg ball that is tied to the end of a 1.5-m light cord is revolved in a horizontal plane, with the cord making a 30° angle with the vertical.

(a) Determine the ball’s speed. (b) If, instead, the ball is revolved so that its

speed is 3.7 m/s, what angle does the cord make with the vertical?

(Check attached image for the diagram.)

Answer:

(a) The ball’s speed, v = 2.06 m/s

(b) The angle the cord makes with the vertical is 50.40⁰

Explanation:

If the ball is revolved in a horizontal plane, it will form a circular trajectory,

the radius of the circle, R = Lsinθ

where;

L is length of the string

The force acting on the ball is given as;

F = mgtanθ

This above is also equal to centripetal force;

$mgTan \theta = \frac{mv^2}{R} \\\\Recall, R = Lsin \theta\\\\mgTan \theta = \frac{mv^2}{Lsin \theta}\\\\v^2 = glTan \theta sin \theta\\\\v = \sqrt{glTan \theta sin \theta} \\\\v = \sqrt{(9.8)(1.5)(Tan30)(sin30)} \\\\v = 2.06 \ m/s$

(b) when the speed is 3.7 m/s

$v = \sqrt{glTan \theta sin \theta} \ \ \ ;square \ both \ sides\\\\v^2 = glTan \theta sin \theta\\\\v^2 = gl(\frac{sin \theta}{cos \theta}) sin \theta\\\\v^2 = \frac{gl*sin^2 \theta}{cos \theta} \\\\v^2 = \frac{gl*(1- cos^2 \theta)}{cos \theta}\\\\gl*(1- cos^2 \theta) = v^2cos \theta\\\\(9.8*1.5)(1- cos^2 \theta) = (3.7^2)cos \theta\\\\14.7 - 14.7cos^2 \theta = 13.69cos \theta\\\\14.7cos^2 \theta + 13.69cos \theta - 14.7 = 0 \ \ \ ; this \ is \ quadratic \ equation\\\\$

$Cos\theta = \frac{13.69\sqrt{13.69^2 -(-4*14.7*14.7)} }{14.7} \\\\Cos \theta = 0.6374\\\\\theta = Cos^{-1}(0.6374)\\\\\theta = 50.40 ^o$

Therefore, the angle the cord makes with the vertical is 50.40⁰

7 0

3 years ago

A cylinder containing the air comprises the systemm. Cycle is completed as follows : (i) 82000 N-m of work is done by the piston

Stella [2.4K]

Answer & Explanation:

1 N-m = 1 Joule

So 82 kJ of energy put into the system during (i).

45 kJ of heat leaves the system, so 82 kJ - 45 kJ = 37 kJ is remaining.

(ii) requires 100 kJ of energy but only 37 kJ is available, so 100 kJ - 37 kJ = 63 kJ of heat energy must be added to the system.

4 0

3 years ago

Scientific knowledge is generally considered to have a positive effect on society. In which situation would scientific knowledge

attashe74 [19]

Scientific knowledge itself cannot have a positive or negative impact on society per se. What can have a negative or positive impact is how this knowledge is being used.

While we all enjoy a beter life due to advancements in medicine and technology for example, this was because people decided they would put certain scientific discoveries into practice and spread them among the people.

The same thing can also be said for negative scientific discoveries. While energy produced in atomic power plants per se isn't harmful, when making an atomic bomb out of it, it can be disastrous. It was the intention of doing something evil with it that might have had a negative impact on society, not the knowledge itself.

5 0

3 years ago

Which requires more energy: lifting a 50 kg sack vertically 2 meters or lifting a 25 kg sack vertically 4 meters?

elena-s [515]

Answer:

c. Both require the same amount of work

Explanation:

GPE = mgh

50 * 10 * 2 = 1000 J

25 * 10 * 4 = 1000 J

Therefore, both are same and require the same amount of work.

Thenk and mark me brainliest :)

3 0

3 years ago

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Which factors will increase the speed of a sound wave in the air?