Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
Explanation:
If a body does not cover a equal distance at a equal interval of time it is said to be non uniform motion...

Answer:
Explanation:
Component of force perpendicular to stick
= F Sin 60°
=√3 / 2 F.
Taking torque about the other end
= √3 / 2 F x 1 Nm
Weight of stick = 60 gm
= 60 x 10⁻³ kg
= 60 x 10⁻³ x 9.8 N
= .588 N
This weight will act from the middle point of stick so torque about the
other end
= .588 x 1 Nm
Balancing these two torques we have
.588 = √3 /2 F

F = 0.679 N
Answer:
lead with Z = 82 is transformed into Bismuth with Z = 73
The Po with Z = 84 becomes Pb with Z = 82
Explanation:
Beta decay occurs when a neutron emits an electron and an anti neutrino from the atomic nucleus, therefore the atomic number of the material increases by one unit.
Pb + e + ν → Bi
lead with Z = 82 is transformed into Bismuth with Z = 73
In alpha decay, a helium nucleus is emitted from the nucleus of the atom, therefore the atomic number decreases by two units.
Po +α → Pb
The Po with Z = 84 becomes Pb with Z = 82