Answer: 6m/s
Explanation:
Using the law of conservation of momentum, the change in momentum of the bodies before collision is equal to the change in momentum after collision.
After collision, the two objects will move at the same velocity (v).
Let mA and mB be the mass of the two objects
uA and uB be their velocities before collision.
v be their velocity after collision
Since the two objects has the same mass, mA= mB= m
Also since object A is at rest, its velocity = 0m/s
Velocity of object B = 12m/s
Mathematically,
mAuA + mBuB = (mA+mB )v
m(0) + m(12) = (m+m)v
0+12m = (2m)v
12m = 2mv
12 = 2v
v = 6m/s
Therefore the speed of the composite body (A B) after the collision is 6m/s
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=

Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =

Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K



The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).
Answer:
Both technicians A and B
Explanation:
Both trailer sway control, hill assist and hill descent controls are additional featires that enhance stability of electronics and their control systems. Majorly, these features track and reduce skidding in electronics, therfore, enhancing electronic system stability. During the process, these newly added features help to automatically apply brakes and direct the sytem where the controller wants to take it.
The answer to this question is 1cm/s
Explanation:
The moment of inertia of each disk is:
Idisk = 1/2 MR²
Using parallel axis theorem, the moment of inertia of each rod is:
Irod = 1/2 mr² + m (R − r)²
The total moment of inertia is:
I = 2Idisk + 5Irod
I = 2 (1/2 MR²) + 5 [1/2 mr² + m (R − r)²]
I = MR² + 5/2 mr² + 5m (R − r)²
Plugging in values:
I = (125 g) (5 cm)² + 5/2 (250 g) (1 cm)² + 5 (250 g) (5 cm − 1 cm)²
I = 23,750 g cm²