Physics 12 energy, work question

In summary, a sandbag stopped a 12 g bullet traveling at 860 m/s and penetrating 24 cm into the sand. To find the time it took for the bullet to stop, the equation ∇p=Ft was used, resulting in a time of 5.6*10^-4 seconds. Using the formula e=1/2mv^2, the average force acting on the bullet was calculated to be 4437.6. However, the data provided does not give enough information to calculate the initial force or time, so additional equations were needed.
  • #1
gdhillon
16
0
Q:A sandbag stops a 12 g bullet which was traveling at 860 m/s. The bullet penetrated a
distance of 24 cm into the sand?
a) How long did it take the bullet to stop?
b) What average force acted on the bullet?
first i used ∇p=Ft so 10.32=18490t t=5.6*10^-4 sec
then i put that into e=1/2mv^2 (to get letter A) so 1/2(.012)860^2= 4437.6
 
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  • #2
gdhillon said:
first i used ∇p=Ft so 10.32=18490t
Where did the 18490 come from? The data tells you neither F nor t, only distance.
 
  • #3
You know the distance traveled by the bullet, it's initial velocity, and it's final velocity. Use a kinematics equation which relates them to find out the acceleration of the bullet. Now use that to find the time it travels for using another kinematics equation. And then use that to calculate the average force using the formula you wrote.
 

Related to Physics 12 energy, work question

1. What is the definition of energy in Physics 12?

In Physics 12, energy is defined as the ability to do work. It is a scalar quantity and is measured in joules (J).

2. Can you explain the concept of work in Physics 12?

In Physics 12, work is defined as the amount of energy transferred when a force is applied over a distance. It is calculated by multiplying the force applied by the distance moved in the direction of the force. The unit for work is also joules (J).

3. How is the principle of conservation of energy applied in Physics 12?

The principle of conservation of energy states that energy cannot be created or destroyed, only transferred from one form to another. In Physics 12, this principle is applied in various equations and problems involving different forms of energy, such as kinetic energy, potential energy, and thermal energy.

4. What is the difference between kinetic energy and potential energy in Physics 12?

Kinetic energy is the energy an object possesses due to its motion, while potential energy is the energy an object possesses due to its position or condition. Kinetic energy is directly proportional to an object's mass and velocity, while potential energy is directly proportional to an object's mass and height, or its position in a force field.

5. How is the concept of work-energy theorem used in Physics 12?

The work-energy theorem states that the net work done on an object is equal to the change in its kinetic energy. In Physics 12, this concept is used to solve problems involving the relationships between work, energy, and forces acting on an object.

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