Calculate the gravitational force of 2 masses of 131 kg and 145 kg if they are 5.2 m apart.

A rifle with a weight of 25 N fires a 4.5-g bullet with a speed of 240 m/s. (a) Find the recoil speed of the rifle. m/s (b) If a

asambeis [7]

Answer:

The recoil speed of the man and rifle is $v_{man}=0.016 ms^{-1}$ .

Explanation:

The expression for the force in terms of mg is as follows;

F=mg

Here, m is the mass and acceleration due to gravity.

Rearrange the expression for mass.

$m=\frac{F}{g}$

Calculate the combined mass of the man and rifle.

$m_{man,rifle}=\frac{650+25}{g}$

Put $g=9.8 ms^{-2}$ .

$m_{man,rifle}=\frac{650+25}{9.8}$

$m_{man,rifle}=68.88 kg$

The expression for the conservation of momentum is as follows as;

$m_{man}u_{man}+m_{bullet}u_{bullet}=m_{man}v_{man}+m_{rifle}v_{man,rifle}$

Here, $m_{man,rifle}$ is the mass of the man and rifle, $m_{rifle}$ is the mass of the rifle, $u_{man},u{bullet}$ are the initial velocities of the man and bullet and $v_{man},v{man,rifle}$ are the final velocities of the man and rifle and rifle.

It is given in the problem that a rifle with a weight of 25 N fires a 4.5-g bullet with a speed of 240 m/s.

Convert mass of rifle from gram to kilogram.

$m_{bullet}=4.5 g$

$m_{bullet}=.0045 kg$

Put $m_{bullet}=.0045 kg$ , $m_{man,rifle}=68.88 kg$ , $u_{man,rifle}=0$ , $v_{bullet}= 240 ms^{-1}$ and $u_{bullet}=0$ .

$m_{man}(0)+m_{bullet}(0)=(68.88)v_{man,rifle}+(.0045)(240)$

$0=(68.88)v_{man,rifle}+(.0045)(240)$

$0=(68.88)v_{man,rifle}+1.08$

$(68.88)v_{man,rifle}=\frac{-1.08}{68.88}$

$v_{man,rifle}=-0.016 ms^{-1}$

Therefore, the recoil speed of the man and rifle is $v_{man}=0.016 ms^{-1}$ .

3 0

2 years ago

A car traveling in a straight line has a velocity of +4.4 m/s. after an acceleration of 0.65 m/s2 , the car's velocity is +8.3 m

nydimaria [60]

Answer:

1.53seconds

Explanation:

Using first equation of motion :

V=U + at

Where final velocity (V) =+8.3m/s

Initial velocity (U) =+4.4m/s

Acceleration (a) = 0.65m/s^2

time(s)=?

V=U + at

+8.3^2 = +4.4 + 0.65 * t

Making t the subject of the formula :

Therefore, t= ( +8.3 - 4.4)/0.65 = 1.53seconds

7 0

2 years ago

A turtle accelerates from a stop at 3m/s/s to the South for 8s. What is the turtle’s final velocity? Show your work and include

andrey2020 [161]

He's accelerating at 3 m/s² . That means his speed is increasing by 3 m/s every second.At the end of 8 seconds, his speed is (8 x 3 m/s) = 24 m/s .He's been moving south for the whole 8 seconds.So at the end of that time, his velocity is 24 m/s south .

5 0

2 years ago

Which of the following statements best states Newton's second law?

icang [17]

I think it's B ,go to physicsclassroom.com Newton's second law

4 0

2 years ago

Do mirrors reflect light

777dan777 [17]

Answer:

Yes, Mirror are a surface that reflects light more perfectly than ordinary objects.

Explanation:

8 0

2 years ago