Exemplar Solution

This is a short answer type question as classified in NCERT Exemplar

Physical state of ice, water and steam are very different but the chemical composition of water in all the three states is H₂O.

This is a short answer type question as classified in NCERT Exemplar

  (a) the greatest volume is occupied by CH₄ and

(b) the smallest volume by NO

According to Avagadro’s Law,

Volume of 1 mole of a gas at STP   =   22.4 L

Now, we know,

1 mole  =     Molar mass

∴   Vol

This is a Long Answer type Questions as classified in NCERT Exemplar

Explanation – as body moving with uniform acceleration a=0

The sum of forces is zero F₁+F₂+F₃=0

a)let F₁, F₂, F₃ be the three forces passing through the point . let F₁and F₂ be in the plane A

so F₃ =- (F₁+F₂) so F₃ is also in plan

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation -initial speed of coin u= 20m/s

Acceleration of elevator =2m/s² acceleration due to gravity = 10m/s²

Effective acceleration =g+a=12m/s²

We know that v=u +at

0= 20+ (-12)t

So t= 20/12=5/3 s

Time of ascent = time of descent

Tot

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation- from the diagram x= t=dx/dt=1m/s

So a_x= 0

From the diagram y =t²

dy/dt=2t  or a_y=d²y/dt²=2m/s²

I_y= ma_y=500 (10^-3) (2) =1N

F_x=ma_x=0

F= $\sqrt[]{F_x^2+F_y^2}$ = 1N

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation- mass of gun =100kg

Mass of ball =1kg and height of cliff = 500m

So horizontal distance travelled by the ball is x = 400m

So h =1/2gt²

500= $\frac{1}{2}10\left(t\right)$ ² so t= 10s

X=ut then u= 400/10=40m/s

 According to principle of conservat

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation-given mass of the block =M

Coefficient of friction between block and the wall = $\mu$

In equilibrium  condition vertical and horizontal component balance each other

So f=mg

And F=N but the force of friction f= $\mu N=\mu F$

  $\mu F=Mg$

F=

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation- in equilibrium, The force mgsin $\theta$ acting on the block A is parallel to the plane should be balanced by the tension in the string

mgsin $\theta =T=F$

and for block B, w=T=F

 from these two above equation 

w=mgsin $\theta$ = 100s

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation- m₁= 5kg, m₂= 3kg

And g= 9.8m/s² and a= 2m/s²

For the upper block T₁-T₂-5g=5a

T₁-T₂= 5 (g+a)

For the lower block T₂-3g =3a

T₂=3 (g+a)=3 (9.8+2)=35.4N

T₁=T₂+5 (g+a)=94.4N

This is a Short Answer type Questions as classified in NCERT Exemplar

Explanation – when the lower thread CD is pulled with a * the thread Cd itself break because the thread CD is not transmitted to the thread Ab instantly.