It transmits energy into the medium through its vibration. More energetic vibration corresponds to larger amplitude. The molecules move back and forth more vigorously. The loudness of a sound is also determined by the sensitivity of the ear.

3 0

3 years ago

A ball thrown vertically upward is caught by the thrower after 4.00 sec. Find the initial velocity of the ball and the maximum h

My name is Ann [436]

Answer:

Initial velocity = 39.2m/s

Maximum height is 78.4m

Explanation:

Given

$Time, t = 4s$

Solving (a): Initial Velocity

Using first law of motion:

$v = u + at$

Where

$v = final\ velocity = 0$

$u = iniital\ velocity = ??$

 $a = acceleration = -g$  [g represents acceleration due to gravity]

$t = 4$

Substitute these value in the above formula:

$v = u + at$

$0 = u - g * 4$

$0 = u - 9.8 * 4$

Take g as 9.8m/s²

$0 = u - 39.2$

$u = 39.2m/s\\$

Hence, initial velocity = 39.2m/s

Solving (b): Maximum Height

This will be solved using second equation of motion

$s = ut + \frac{1}{2}at^2$

This becomes

$s = ut - \frac{1}{2}gt^2$

Substitute values for u, t and g

$s = 39.2 * 4 - \frac{1}{2} * 9.8 * 4^2$

$s = 156.8 - 78.4$

$s = 78.4$

Hence, the maximum height is 78.4m

7 0

4 years ago

A 1500 kg car traveling to the north is slowed down uniformly from initial velocity of 20 m/s by a 6000 N braking force acting o

aev [14]

Answer:

12 m/s

Explanation:

Given data

Mass m= 1500kg

intitial velocity u= 20m/s

force F= 6000N

time t= 2 seconds

Required

The final velocity v

From

Ft= mΔv

Ft= m(u-v)

substitute

6000*2= 1500(20-v)

solve for v

12000= 30000- 1500v

collect like terms

12000-30000= -1500v

-18000= -1500v

divide both sides by -1500v

v= 18000/1500

v=12 m/s

Hence the velccity is 12 m/s

3 0

3 years ago

A push or a pull is called _____. User: The metric unit of force is the _____.

A push or a pull is called _. User: The metric unit of force is the _.