Question

33. A stone is tied to one end of a string and whirled in a horizontal circle of radius 1 m at 20 revolutions

per minute. Calculate the angular velocity and linear speed of the stone. Also find the centripetal

acceleration.

34. A force of 10 N acts for 20 second on a body of mass 2 kg initially at rest. Calculate the energy required

by the body and the work done by the applied force.

35. If the earth has a mass 9 times and radius twice of the planet mars, calculate the minimum speed

required by a rocket to pull out of the gravitational force of Mars. Escape speed for an object on the

surface of the earth is 11.2 kms-1

.​

Answer 1

Answer:

Given length of the string l= 1 m also angular velocity ω=

44

22

revolution/second.

We know linear velocity v=ω×r

Thus velocity v=

44

22

×1=0.5 m/s

And we know centripetal or radial acceleration a

c

=

r

v

2

Thus a

c

=0.25m/s

2

2- Force = mass × acceleration

F=10N

m=2kg

then,

a=

m

F

=

2

10

=5m/s

2

(i) Now,

u=0

t=3sec

v=u+at=0+3×5=15m/s

(ii)Initialmomentum=mu=2×0=0

Finalmomentum=mv=2×15=30kg−m/s

Change in momentum=Final momentum - Initial momentum

=30−0=30kg−m/s

3- Given: Me = 9 Mm, and Re = 2 Rm, ve (escape speed on surface of Earth) = 11.2 km/s

Let Vm be the speed required to pull out of the gravitational force of mars.

We know that

and

Dividing, we get

⇒ vm = 5.3 km/s

Answer 2

✧═════════════•❁❀❁•══════════════✧$\huge\color{Pink}\boxed{\colorbox{Black}{❥Mysteryboy01}}$

✧═════════════•❁❀❁•══════════════✧

$\huge\color{lime}\boxed{\colorbox{black}{⭐God Bless U⭐}}$

$\huge\star\underline{\mathtt\orange{❥Good} \mathfrak\blue{Af }\mathfrak\blue{t} \mathbb\purple{ er}\mathtt\orange{n} \mathbb\pink{oon}}\star\:$

$\huge\star\huge{ \pink{\bold {\underline {\underline {\red {Great Day }}}}}} \star$

$\huge\blue\bigstar\pink{Be Safe Always }$

$\huge\fbox \red{✔Que} {\colorbox{crimson}{est}}\fbox\red{ion✔}$

The Question is Give below

$\huge\color{Red}\boxed{\colorbox{black}{♡Answer ♡}}$

The Answer is in Attachment

$\huge\color{cyan}\boxed{\colorbox{black}{Cute boy❤}}$

$\huge\color{cyan}\boxed{\colorbox{black}{Mark as Brainlist ❤}}$