A rifle with a weight of 35 N fires a 4.0 g bullet with a speed of 250 m/s.
(a) Find the recoil speed of the rifle.
___m/s
(b) If a 700 N man holds the rifle firmly against his shoulder, find the recoil speed of the man and rifle.
___m/s
Ah, do this the same way we did the guy on skates.
I need help with the same question but different numbers. how do you solve it?
Go look at the last problem I did with jake, wait a sec and I will copy it here, conservation of momentum with zero before the shot.
A 715 N man stands in the middle of a frozen pond of radius 10.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore at a speed of 10.0 m/s. How long does it take him to reach the south shore?
* Physics..help please - Damon, Wednesday, October 6, 2010 at 3:51pm
first find his mass in kilograms
m = 715 / 9.81
then use conservation of momentum
(total of 0 before the toss)
0 = (715/9.81) v - 1.2 * 10
solve for v
how long does it take to go 10 meters at v meters/second?
I still can't figure it out with this question. i get the one you did with jake but not this one.
A rifle with a weight of 35 N fires a 4.0 g bullet with a speed of 250 m/s.
(a) Find the recoil speed of the rifle.
___m/s
------------------------------
All is still. Momentum = 0
A shot rings out.
The rifle goes left, the bullet goes right.
Momentum is STILL zero (no outside forces)
m rifle = 35/9.8
m bullet = .004
so
0 = -(35/9.8) v + .004 * 250
for the second part add the mass of the man (700/9.8) to the mass of the rifle and repeat the calculation
A bullet is shot from a rifle aimed horizontally at the same time a bullet is dropped from the same height as the gun's barrel. Which bullet hits the ground first?
To find the recoil speed of the rifle, we can use the principle of conservation of momentum. According to this principle, the total momentum before the bullet is fired is equal to the total momentum after the bullet is fired, considering the system of the rifle and the bullet.
(a)
1. Identify the initial momentum (before the bullet is fired) and the final momentum (after the bullet is fired).
- The initial momentum is the momentum of the combined system of the rifle and the bullet, before the bullet is fired.
- The final momentum is the momentum of the combined system of the rifle and the bullet, after the bullet is fired, taking into account the recoil of the rifle.
2. Calculate the initial momentum:
- The initial momentum (P_initial) is given by the product of the total mass and the initial velocity.
- The total mass is the sum of the mass of the bullet (converted into kg) and the mass of the rifle (converted into kg).
- The initial velocity for the bullet, in this case, is the given speed of 250 m/s, while the initial velocity of the rifle is 0 m/s (at rest).
- Therefore, the initial momentum can be calculated using the formula: P_initial = (mass_bullet + mass_rifle) * 0 + mass_bullet * speed_bullet
3. Calculate the final momentum:
- The final momentum (P_final) is given by the product of the total mass (considering the bullet and the rifle) and the final velocity (recoil speed of the rifle).
- The total mass remains the same as in the initial momentum calculation.
- The final velocity for the bullet is the given speed of 250 m/s, but the final velocity for the rifle needs to be determined.
4. Apply the principle of conservation of momentum:
- According to the principle of conservation of momentum, the initial momentum is equal to the final momentum.
- Therefore, P_initial = P_final.
- Substitute the calculated values from steps 2 and 3 to get the equation: (mass_bullet + mass_rifle) * 0 + mass_bullet * speed_bullet = (mass_bullet + mass_rifle) * recoil_speed_rifle.
5. Solve the equation for recoil_speed_rifle to find the recoil speed of the rifle.
(b)
To find the recoil speed of the man and the rifle when a 700 N man holds the rifle firmly against his shoulder, we can use the same approach as in part (a). The only difference is that the mass of the system will now include the mass of the man, and the external force applied by the man must also be considered.
1. Identify the initial momentum (before the bullet is fired) and the final momentum (after the bullet is fired).
- The initial momentum is the momentum of the combined system of the rifle, bullet, and the man, before the bullet is fired.
- The final momentum is the momentum of the combined system of the rifle, bullet, and the man, after the bullet is fired, taking into account the recoil of the rifle and the man.
2. Calculate the initial momentum:
- The initial momentum (P_initial) is given by the product of the total mass and the initial velocity.
- The total mass is the sum of the mass of the bullet, the mass of the rifle, and the mass of the man (converted into kg).
- The initial velocity for the bullet, in this case, is the given speed of 250 m/s, while the initial velocity of the rifle and the man is 0 m/s (at rest).
- Therefore, the initial momentum can be calculated using the formula: P_initial = (mass_bullet + mass_rifle + mass_man) * 0 + mass_bullet * speed_bullet.
3. Calculate the final momentum:
- The final momentum (P_final) is given by the product of the total mass (considering the bullet, the rifle, and the man) and the final velocity (recoil speed of the rifle and the man).
- The total mass remains the same as in the initial momentum calculation.
- The final velocity for the bullet is the given speed of 250 m/s, but the final velocity for the rifle and the man needs to be determined.
4. Apply the principle of conservation of momentum:
- According to the principle of conservation of momentum, the initial momentum is equal to the final momentum.
- Therefore, P_initial = P_final.
- Substitute the calculated values from steps 2 and 3 to get the equation: (mass_bullet + mass_rifle + mass_man) * 0 + mass_bullet * speed_bullet = (mass_bullet + mass_rifle + mass_man) * recoil_speed_rifle_and_man.
5. Solve the equation for recoil_speed_rifle_and_man to find the recoil speed of the rifle and the man.