Answer:
3.25 seconds
Explanation:
It is given that,
A person throws a baseball from height of 7 feet with an initial vertical velocity of 50 feet per second. The equation for his motion is as follows :

Where
s is the height in feet
For the given condition, the equation becomes:

When it hits the ground, h = 0
i.e.

It is a quadratic equation, we find the value of t,
t = 3.25 seconds and t = -0.134 s
Neglecting negative value
Hence, for 3.25 seconds the baseball is in the air before it hits the ground.
Microscopes with life science and physics
Answer:
4A
Explanation:
According to ohm's law;
E = IRt where;
E is the source voltage = 24volts
I is the total current flowing in the circuit = ?
Rt is the total effective resistance in the circuit.
To find Rt, we will resolve the resistors in parallel first.
Since 6ohms and 12ohms resistors are in parallel, their effective resistance will give;
1/R = 1/6+1/12
1/R= 2+1/12
1/R = 3/12
3R = 12
R = 4ohms.
This resistor will now be in series with the 2.0ohms resistor to finally have;
Rt = 4+2
Rt = 6ohms
From the ohms law formula;
I = E/Rt
I = 24/6
I = 4Amperes
The total current in the circuit is 4A
This same currents will flow in the 2ohms resistor since same current flows in a series connected resistors.
Answer:
c) The wavelength decreases but the frequency remains the same.
Explanation:
Light travels at different speed in different mediums.
Refractive index is equal to velocity of the light 'c' in empty space divided by the velocity 'v' in the substance.
Or ,
n = c/v.
<u>The frequency of the light does not change but the wavelength of the light changes with change in the speed.</u>
c = frequency × Wavelength
Frequency is constant,
The formula can be written as:
n = λ / λn.
Where,
λn is the wavelength in the medium
λ is the wavelength in vacuum
<u>When the light travels to glass, it speed slows down and also the wavelength decreases as both are directly proportional. There will be no effect on frequency.</u>
Not sure this is a physics question (probably biology).
Anyway, the correct answer is A):
"Plasticity helps us to adapt to our environment. It also generally decreases with age".
Plasticity is the ability to adapt to the environment. Since this ability is linked with brain functions, and brain functions worsen with age, then plasticity decreases with age.