Most geologists accept radiometric dating techniques as valid because radioactive elements decay at a constant and measurable rate.
Answer: Option C
<u>Explanation:</u>
Scientists prefer radioactive dating to carbon dating because it is more accurate in measuring. The analysis depends upon the radioactive decay of radioactive isotopes of any matter in a given rock or soil.
The parent atoms and daughter atoms are compared while studying, and hence age can be calculated easily. Radioactive decay depends upon the given half-life of the atom, which is a constant and is known. So, it would be very easy to calculate the number of progeny atoms and parent atoms and find out their age.
The correct answer is the recoil velocity of the cannon is equal to 90m/s.
Answer:
acceleration a= 0.1344 m/sec^2
Explanation:
Given
mass of the object m= 72 kg
Force applied with help of rope= 358 N
Acceleration due to gravity= 9.81 m/sec^2
Since there is no force acting on the person and rope
then T=F
and from the FBD we can write
2T- mg= ma ,or
2F- mg= ma
![a=\frac{2F-mg}{m}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B2F-mg%7D%7Bm%7D)
now putting the values we get
![a=\frac{2F-mg}{m}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B2F-mg%7D%7Bm%7D)
![a=\frac{2\times358-72\times9.81}{72}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B2%5Ctimes358-72%5Ctimes9.81%7D%7B72%7D)
on calculating we get acceleration a= 0.1344 m/sec^2
Answer:
at t=46/22, x=24 699/1210 ≈ 24.56m
Explanation:
The general equation for location is:
x(t) = x₀ + v₀·t + 1/2 a·t²
Where:
x(t) is the location at time t. Let's say this is the height above the base of the cliff.
x₀ is the starting position. At the base of the cliff we'll take x₀=0 and at the top x₀=46.0
v₀ is the initial velocity. For the ball it is 0, for the stone it is 22.0.
a is the standard gravity. In this example it is pointed downwards at -9.8 m/s².
Now that we have this formula, we have to write it two times, once for the ball and once for the stone, and then figure out for which t they are equal, which is the point of collision.
Ball: x(t) = 46.0 + 0 - 1/2*9.8 t²
Stone: x(t) = 0 + 22·t - 1/2*9.8 t²
Since both objects are subject to the same gravity, the 1/2 a·t² term cancels out on both side, and what we're left with is actually quite a simple equation:
46 = 22·t
so t = 46/22 ≈ 2.09
Put this t back into either original (i.e., with the quadratic term) equation and get:
x(46/22) = 46 - 1/2 * 9.806 * (46/22)² ≈ 24.56 m
In case of an object sitting at rest on another base, there are two equal and opposite forces – Normal force and the gravity.
Answer: Option A
<u>Explanation:
</u>
When an object is placed at rest position on another object, there is a force exerted by the surfaces of the two contact objects. This force is denoted as Normal Force.
When an object such as a box is placed on a shelf, its surface exerts a contact force on the base of the shelf- The Normal force directed upward. Meanwhile, the gravity stays at its action and tries to pull the box towards itself.
Both of these forces however are equal and opposite and therefore, there is zero net force on the box. That's why it remains at rest, holding on Newton's third law.