The diameter of a helium atom is about 1 3 102 pm. Suppose that we could line up helium atoms side by side in contact with one another. Approximately how many atoms would it take to make the distance from end to end 1 cm

1 × 10⁸ He atoms

Explanation:

Step 1: Given data

Step 2: Convert "d" to meters

We will use the conversion factor 1 m = 10¹² pm.

1 × 10² pm × (1 m / 10¹² pm) = 1 × 10⁻¹⁰ m

Step 3: Convert "D" to meters

We will use the conversion factor 1 m = 100 cm.

1 cm × (1 m / 100 cm) = 0.01 m

Step 4: Calculate the number of atoms of He required

We will use the following expression.

D/d = 0.01 m / 1 × 10⁻¹⁰ m = 1 × 10⁸

i think its 100

i hope this !

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied