Density = (mass) divided by (volume)
We know the mass (2.5 g). We need to find the volume.
The penny is a very short cylinder.
The volume of a cylinder is (π · radius² · height).
The penny's radius is 1/2 of its diameter = 9.775 mm.
The 'height' of the cylinder is the penny's thickness = 1.55 mm.
Volume = (π) (9.775 mm)² (1.55 mm)
= (π) (95.55 mm²) (1.55 mm)
= (π) (148.1 mm³)
= 465.3 mm³
We know the volume now. So we could state the density of the penny,
but nobody will understand what we have. Here it is:
mass/volume = 2.5 g / 465.3 mm³ = 0.0054 g/mm³ .
Nobody every talks about density in units of ' gram/(millimeter)³ ' .
It's always ' gram / (centimeter)³ '.
So we have to convert our number for the volume.
(0.0054 g/mm³) x (10 mm / cm)³
= (0.0054 x 1,000) g/cm³
= 5.37 g/cm³ .
This isn't actually very close to what the US mint says for the density
of a penny, but it's in a much better ball park than 0.0054 was.
She threw the marshmallow at a speed of around 4.76 m/s.The formula for the horizontal range gives the velocity.
<h3>What is projectile motion?</h3>
The motion of an item hurled or projected into the air, subject only to gravity's acceleration, is known as projectile motion.
The item is known as a projectile, and the course it takes is known as a trajectory. Falling object motion is a simple one-dimensional kind of projectile motion with no horizontal movement.
Given data;
The marshmallow was thrown at a distance of 2 meters
Range,R = 3 m
Initial velocity,u
The angle at which the marshmallow was thrown,θ = 30°
The acceleration due to gravity,g = 9.81 m/s²
The projectile's motion is divided into two parts: horizontal and vertical motion.

Hence, she throws the marshmallow at a speed of 4.76 m/sec.
To learn more about the projectile motion refer to the link;
brainly.com/question/11049671
#SPJ1
Answer:
(A). The speed of the ions is 
(B). The radius of curvature of a singly charged lithium ion is 
Explanation:
Given that,
Electric field = 60000 N/C
Magnetic field = 0.0500 T
(A). We need to calculate the velocity
For no deflection





(B). We need to calculate the radius
Using magnetic force balance by centripetal force


Put the value into the formula


Hence, (A). The speed of the ions is 
(B). The radius of curvature of a singly charged lithium ion is 
Answer: Resting Membrane Potential
Explanation:
The <u>resting membrane potential</u> refers to the difference in voltage between the inside and outside of the cell membrane when the cell is at physiological rest. It should be noted that <u>the cell membrane is a selective semipermeable barrier, which only allows the transit through it of certain molecules and prevents the transit of others.
</u>
This selectivity causes an uneven distribution of charged particles (ions), as the membrane only accepts some types of ions.
Now, in the case of neurons, which are electrically excitable nerve cells; the transport of electrical signals is due to these changes in the permeability and asymmetric distribution of ions (mainly sodium and potassium) when the neuron is not excited (at rest).
Answer: d
Explanation: divide it by 4