Chapter 9 FORCE AND LAWS OF MOTION

Define Force, write S I and C G S unit of force .

Solution : Definition “The force is the vector product of mass (m) and acceleration (a). ” Formula for Force Force = mass x acceleration The equation or the formula for force can mathematically be expressed in the form of: F = m a Where , F = force, m = mass , a = acceleration …

Define Force, write S I and C G S unit of force . Read More »

CONSERVATION LAWS OF MOMENTUM

All conservation laws such as conservation of momentum, energy, angular momentum, charge etc. are considered to be fundamental laws in physics. These are based on observations and experiments. It is important to remember that a conservation law cannot be proved. It can be verified, or disproved, by experiments. An experiment whose result isin conformity with …

CONSERVATION LAWS OF MOMENTUM Read More »

Two hockey players of opposite teams, while trying to hit a hockey ball on the ground collide and immediately become entangled. One has a mass of 60 kg and was moving with a velocity 5.0 m s–1 while the other has a mass of 55 kg and was moving faster with a velocity 6.0 m s–1 towards the first player. In which direction and with what velocity will they move after they become entangled? Assume that the frictional force acting between the feet of the two players and ground is negligible.

Solution: Let the first player be moving from left to right. By convention left to right is taken as the positive direction and thusright to left is the negative direction . If symbols m and u represent the mass and initial velocity of the twoplayers, respectively. Subscripts 1 and 2 in these physical quantities refer …

Two hockey players of opposite teams, while trying to hit a hockey ball on the ground collide and immediately become entangled. One has a mass of 60 kg and was moving with a velocity 5.0 m s–1 while the other has a mass of 55 kg and was moving faster with a velocity 6.0 m s–1 towards the first player. In which direction and with what velocity will they move after they become entangled? Assume that the frictional force acting between the feet of the two players and ground is negligible. Read More »

A girl of mass 40 kg jumps with a horizontal velocity of 5 m s-1 onto a stationary cart with frictionless wheels. The mass of the cart is 3 kg. What is her velocity as the cart starts moving? Assume that there is no external unbalanced force working in the horizontal direction.

Solution:Let v be the velocity of the girl on the cart as the cart starts moving.The total momenta of the girl and cart before the interaction= 40 kg × 5 m s–1 + 3 kg × 0 m s–1= 200 kg m s–1.Total momenta after the interaction= (40 + 3) kg × v m s–1= …

A girl of mass 40 kg jumps with a horizontal velocity of 5 m s-1 onto a stationary cart with frictionless wheels. The mass of the cart is 3 kg. What is her velocity as the cart starts moving? Assume that there is no external unbalanced force working in the horizontal direction. Read More »

A bullet of mass 20 g is horizontally fired with a velocity 150 m s-1 from a pistol of mass 2 kg. What is the recoil velocity of the pistol?

Solution:We have the mass of bullet,m1 = 20 g (= 0.02 kg) and the mass ofthe pistol, m2 = 2 kg; initial velocities of the bullet (u1 ) and pistol (u2 ) = 0,respectively. The final velocity of the bullet, v1 = + 150 m s-1. The directionof bullet is taken from left to right …

A bullet of mass 20 g is horizontally fired with a velocity 150 m s-1 from a pistol of mass 2 kg. What is the recoil velocity of the pistol? Read More »