The last one, handmade gifts require more of the givers time!
Work done = 0.5*m*[(v2)^2 - (v1)^2]
where m is mass,
v2 and v1 are the velocities.
Given that m = 1.50 x 10^3 kg, v2 = -15 m/s (decelerates), v1 = 25 kg,
Work done = 0.5 * 1.50 x 10^3 * ((-15)^2 - 25^2) = 3 x 10^5 joules
Just ignore the negative value for the final result because work is a scalar quantity.
Answer:
A closed system.
Explanation:
The three major types of system are: open, closed and isolated. Open system interacts with its surroundings with respect to its particles and energy. A closed system interacts with its surroundings with respect to energy but not its particles. While an isolated system does not interact with its surroundings in any way.
Therefore, after the jar is sealed, it is an example of a closed system. This is because the emitted gas could not escape into the surroundings, but thermal energy was emitted into its surroundings after the chemical reaction has taken place.
Answer:
In the more scientific viewpoint, the most important thing that she must do is caring for her hygiene and put some plastic gloves in her hands.
This is because there are lots of particles that can be retained in the hands (dust, skin, etc), and when examining the scene, she may drop some of these particles, "contaminating" the scene in this way with information that only will affect the investigation.
So the most important thing is being prepared to not affect anything in the crime scene
