Incomplete question as the unit of volume is not written correctly.So the complete question is here:
A straightforward method of finding the density of an object is to measure its mass and then measure its volume by submerging it in a graduated cylinder. What is the density of a 240-g rock that displaces 89.0 cm³?
Answer:

Explanation:
Given data
Mass m=240g
Volume V=89.0 cm³
To find
Density d
Solution
If rock displaces 89.0 cm³ of water means volume of rock is also 89cm³
So

10.92N
Explanation:
Given parameters:
Mass of truck = 2.964kg
Velocity of truck = 7m/s
Time taken = 1.9s
Unknown:
Average force on the car = ?
Solution:
According to newton's third law of motion "action and reaction are equal and opposite".
The force with which the truck struck the fence is the same as the force the fence acted on the truck with but in another direction.
From newton's second law:
Force = mass x acceleration
We know that acceleration is the change in velocity with time;
acceleration =
Force = mass x
Force =
= 10.92N
learn more:
Newton's laws brainly.com/question/11411375
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Answer:
The radius of the gold nucleus is 7.1x10⁻¹⁵m
Explanation:
The nearest distance is:
(eq. 1)
Where
z = atomic number of gold = 79
e = electron charge = 1.6x10⁻¹⁹C
k = electrostatic constant = 9x10⁹Nm²C²
energy of the particle = 32 MeV = 5.12x10⁻¹²J
At the potential energy is zero, all the energy will be kinetic energy:

Where
m = 4 mp = mass of proton

Replacing in equation 1

Answer:
Friction
Explanation:
Friction is a force that slows down moving objects. If you roll a ball across a shaggy rug, you can see that there are lumps and bumps in the rug that make the ball slow down. The rubbing, or friction, between the ball and the rug is what makes the ball stop rolling. External Force is required.