**Answer:**

**v=9.6 km/s**

**Explanation:**

Given that

The mass of the car = m

The mass of the truck = 4 m

The velocity of the truck ,u= 12 km/s

The final velocity when they stick = v

If there is no any external force on the system then the total linear momentum of the system will be conserve.

Pi = Pf

m x 0 + 4 m x 12 = (m + 4 m) x v

0 + 48 m = 5 m v

5 v = 48

**v=9.6 km/s**

**Therefore the final velocity will be 9.6 km/s.**

**Answer:**

5.76×10⁻¹⁷ C

**Explanation:**

An electron has a charge of 1.6×10⁻¹⁹ C.

360 × (1.6×10⁻¹⁹ C) = 5.76×10⁻¹⁷ C

Point out that when water<span> freezes, the </span>water<span> molecules have slowed down enough that their attractions arrange them into fixed positions. </span>Water<span> molecules freeze in a hexagonal pattern and the molecules are further apart than they were in liquid </span>water<span>. Note: The molecules in </span>ice<span> would be vibrating.</span>

Answer:

The answer is that there is no magnetic force on the wire. The force on a wire is the cross product of the current thru it and the magnetic field it is in. In your case, both are parallel and the cross product is therefore zero.

Explanation:

F = (n x i)2 x magnetic constant x a / (2 x g2)

Where,

F = Force, i = Current, g = Length of the gap between the solenoid and a piece of metal, a = Area n = Number of turns, Magnetic constant = 4 x PI x 10-7.