B. the reason we must wear seat belts
Answer:
1,3
Explanation:
As the acceleration is -10m/s^2 , that means deceleration is occurring. That means, the object is slowing down.
v=u-at
or, 0=80-10t
or, t=8 seconds
So, the object will stop in 8 seconds.
So, the correct answers are 1 and 3.
Hope, this helps you.
Test:
Performing a Litmus Test
Result:
Litmus paper gives the user a general indication of acidity or alkalinity as it correlates to the shade of red or blue that the paper turns.
- To test the pH of a substance, dip a strip of litmus paper into the solution or use a dropper or pipette to drip a small amount of solution onto the litmus paper.
- Blue litmus paper can indicate an acid with a pH between 4 and 5 or lower.
- Red litmus paper can show a base with a pH greater than 8.
- If a solution has a pH between 5 and 8, it will show little color change on the litmus paper.
- A base tested with blue litmus paper will not show any color change, nor will an acid tested with red litmus paper register a change in color.
Answer:
D = 2.38 m
Explanation:
This exercise is a diffraction problem where we must be able to separate the license plate numbers, so we must use a criterion to know when two light sources are separated, let's use the Rayleigh criterion, according to this criterion two light sources are separated if The maximum diffraction of a point coincides with the first minimum of the second point, so we can use the diffraction equation for a slit
a sin θ = m λ
Where the first minimum occurs for m = 1, as in these experiments the angle is very small, we can approximate the sine to the angle
θ = λ / a
Also when we use a circular aperture instead of slits, we must use polar coordinates, which introduce a numerical constant
θ = 1.22 λ / D
Where D is the circular tightness
Let's apply this equation to our case
D = 1.22 λ / θ
To calculate the angles let's use trigonometry
tan θ = y / x
θ = tan⁻¹ y / x
θ = tan⁻¹ (4.30 10⁻² / 140 10³)
θ = tan⁻¹ (3.07 10⁻⁷)
θ = 3.07 10⁻⁷ rad
Let's calculate
D = 1.22 600 10⁻⁹ / 3.07 10⁻⁷
D = 2.38 m
Instantaneous velocity, on the other hand, describes the motion of a body at one particular moment in time. Acceleration is a vector which shows the direction and magnitude of changes in velocity. Its standard units are meters per second per second, or meters per second squared. (this is for number 3)