Question

7. A 500 kg car goes around turn in the road that has a radius of curvature of 5 m. The car is traveling at a constant speed of 10 m/s.

(i) What is the centripetal force required to keep the car from sliding out as it goes around the turn?

(ii) What must be the coefficient of friction between the tires of the car and the road in order for the car to not sliding as it goes around the turn?

8. A rigid object with moment of inertia 25 Kg m^2 is spinning around a fixed axis with angular speed of 10 rad/s. A constant torque of 50 Nm is applied in a direction that slows down the rotation, for 2 seconds.

(i) Calculate the angular speed of the object at t = 5 s.

(ii) Calculate the kinetic energy of the object at t = 5 s.

9.A disc of moment of inertia 10 kg m^2 about its center rotates about the center with an angular velocity of 20 rad/s. Calculate:

(i) its rotational energy

(ii) its angular momentum about the center

(iii) the number of revolutions per second of the disc

10.A constant torque of 100 N m turns a wheel which has a moment of inertia 10 kg ms^2 about its center. Find:

(i) the angular velocity gained in 2 second

(ii) the kinetic energy gained in 2 seconds.

11. Calculate the K.E. of the earth due to its rotation about its own axis. Mass of the earth is 6 x10^24 kg and radius of the earth is 6400 km.

12. The moment of inertia of a wheel is 1000 kgm^2. At a given instant, its angular velocity is 10 rad/s. After the wheel rotates through an angle of 100 radian, the wheel’s angular velocity is 100 rad/s. Calculate,

(i) the torque applied on the wheel

(ii) the increase in rotational kinetic energy

13. A disc of mass 5 kg and radius 40 cm rotates about an axis passing through its center and perpendicular to its plane. It makes 10 revolutions in one second. Calculate its ,

(i) rotational KE

(ii) angular momentum

Answer 1

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