The loudness of a sound is inversely proportional to the square of your distance from the source of the sound. if your friend is

Answer:

1350 m/s

Clarification:

Bullet speed

The bullet travels 450 m

Sound travels a distance of 450 m

Using the equation S= V × t

==> t= S/V

Thus, the time for the bullet t1=450/vb

and the sound's travel time t2=450/vs

Given that there's a 1/2 sec interval from when the shot is fired to the moment the shooter hears the sound

==>  t1+t2= 1/2 sec

==> 450/vb+450/vs=0.5sec  ---- (1)

At a distance 'x' from both the gun and target, it takes 3 seconds for a person to hear the bullet sound from firing to impact.

Firing sound duration

n

Distance =x m

Speed of sound = V

time =T1

==> T1 = x/vs

During this time period, the bullet covers 450 m and the sound of impact travels a distance 'x'

The time taken for sound = 450/vb

The time it takes sound to travel distance 'x'= x/vs

therefore let T2= 450/vb + x/vs

However, all this occurs within 3 seconds, i.e., T = 3 sec

because firing takes place before hitting the target, implying the strike sound is heard in time T = T2-T1= 450/vb + x/vs -x/vs

Making T= 3sec

==> 3= 450/vb

==> vb= 1350 m/s

From equations 1 and 2

applying the same principle, in 3 seconds the observer sees the bullet travel 450 m and perceives the sound

The work done can be calculated using the equation:

Work = Force x Distance = Change in kinetic energy

The kinetic energy is derived using the following formula: KE = (1/2)*m*v^2
Thus, the change in kinetic energy is calculated as (1/2)*m*(Vf)^2 - (1/2)*m*(Vo)^2

Where:

Vf represents the final speed = 90 kph = 25 m/s
Vo denotes the initial speed = 72 kph = 20 m/s

By substituting in the given values:

Work = (1/2)*2500*(25^2) - (1/2)*2500*(20^2) = 281250 J, which can also be represented as 2.8 x 10^5 Joules.

The correct choice among the options is A.

The answer is 13900589.

Force F = 1535.86 N The amount of force needed for his wife to maintain her hold on their child during the impact is 1535.86 N Given: Mass of toddler m = 13 kg Velocity v = 37 mi/h = 37 × 0.44704 m/s = 16.54 m/s Impulse time t = 0.14 seconds Using the impulse momentum principle, Impulse = change in momentum Ft = m(∆v) Force F = m(∆v)/t ∆v = 16.54 m/s F = 13×16.54/0.14 Thus, Force F = 1535.86 N