Answer:
v = 16.11 m / s
Explanation:
For this exercise we must use the principle of conservation of energy. We set a reference system on the part of the platform without elongation
starting point. When the spring is compressed
Em₀ = K_e + U = ½ k x² + m g x ’
final point. The point where it leaves the platform
Em_f = K = ½ m v²
energy is conserved
Em₀ = Em_f
½ k x² + m g x ’= ½ m v²
v² =
x² + g x
let's calculate
v² =
1.25² + 9.8 1.25
v² = 247.159 + 12.25 = 259.409
v = 16.11 m / s
Ans: C) Solid
Explanation: We will look into different states
A) Liquid : In liquid state molecules are not very tightly bound to each other. So, they have no fixed shape . They take the shape of container in which they are kept.
B) Gas : In gaseous state molecules are very loosely bound so they have very less intermolecular forces so they have much more freedom of movement.So, it will be also not correct.
D) Plasma : In Plasma state approximately equal amount of positive or negative charges are there, although its a type of hot ionized gaseous state but but due its different properties then other gases it is considered the 'fourth' state. And it also can't maintain it's definite shape and volume.So we will eliminate that also.
C) Solid : Finally we are left with solid state. Here molecules are tightly bound to each other . So, it doesn't change its shape and volume when kept in different container.
So 'Solid' state is the correct choice.
Hope it helps!!!
Answer:
A = 70cm³
B= 805 grams
Explanation:
(a) V = L×B×H
= 7cm × 5cm × 2cm
= 35cm × 2cm
= 70cm³
(b) Mass= volume × Density
= 70cm³ × 11.5g/cm³
=805 grams
I hope this will help you ...
by momentum conservation we can say
![P_i = P_f](https://tex.z-dn.net/?f=P_i%20%3D%20P_f)
since gun and bullet was initially at rest so initial momentum of both must be ZERO
![0 = m_1v_{1f} + m_2v_{2f}](https://tex.z-dn.net/?f=0%20%3D%20m_1v_%7B1f%7D%20%2B%20m_2v_%7B2f%7D)
![0 = 3* 10^{-3}* 3000 + 1 * v_{2f}](https://tex.z-dn.net/?f=0%20%3D%203%2A%2010%5E%7B-3%7D%2A%203000%20%2B%201%20%2A%20v_%7B2f%7D)
![0 = 9 + v_{2f}](https://tex.z-dn.net/?f=0%20%3D%209%20%2B%20v_%7B2f%7D)
![v_{2f} = - 9 m/s](https://tex.z-dn.net/?f=v_%7B2f%7D%20%3D%20-%209%20m%2Fs)
<em>so it will recoil back with speed 9 m/s</em>