A physical quantity is a property of a material or system that can be quantified by measurement. A physical quantity can be expressed as the combination of a numerical value and a unit. For example, the physical quantity mass can be quantified as n kg, where n is the numerical value and kg is the unit.
The atom's atomic number is the number of protons in its nucleus.
Acceleration=
Velocity Final - Velocity Initial
————————————————-
Distance
Vf =0m/s because truck came to complete stop
Vi=28m/s
D=342m
0-28
——— =28.1m/s^2
342
Answer:
100kg
Explanation:
Momentum is defined as the product of mass times velocity:
The total momentum M must be equal to the sum of momentums of the system components, in this case the momentum of the lady plus the momentum of the cart:
since both the woman and the shopping cart have the same velocity:
the equation becomes:
and since we need the mass of the cart we solve for 
:
the values given by the problem are the following:
total momentum: 
mass of the woman: 
velocity: 
we substitute all of them in the equation to find the mass of the shopping cart:
the mass of the cart is 100kg.
Answer:
Frames of reference.
For measuring the physical quantities you have to rely on something as a reference point or a standard value. In the case of physical quantities that are vectors, and an abstract coordinate system is required to express it clearly.
Let us consider a body located on a ship at some point. We can measure its distance from a ship or from the terrace of the building. Hence, we are assigning a coordinate system with respect to a person standing on the ship and terrace. These coordinate systems are called the frames of reference.
While measuring the distance, both coordinate system gives specific values for the same location with regard to the frames of reference.
When the ship is moving, the person on the terrace observes that his values of the distance change. But the person on the ship did not observe any change with respect to his coordinate system.
Similarly, If a person considers a moving train as his frame of reference where his coordinate system is in motion, he finds the things that are stationary on earth seem to move.
The train is his frame of reference which has a velocity with respect to Earth.
Therefore, anything that is stationary with respect to the ground seems to be in motion with respect to his frame of reference.
