Answer:
In light waves, the electromagnetic fields oscillate perpendicular to the direction of propagation. Hence, sound waves are longitudinal waves whereas light waves are transverse waves.
Answer:
1.785 m/s
Explanation:
The momentum can be calculated using the expression below
M1 *V1 + M2 * V2 = (M1+M2) V3
M1= mass of van=9000 kg
M2= mass of car= 850kg
V3= velocity of entangled car
V1= Velocity of the van= 0
V2= velocity of the car= 5 m/ s
Substitute the values
(900×0) + (500×5)=( 900+500)× V3
2500=1400 V3
V3=2500/1400
V3= 1.785 m/s
Hence, velocity of the entangled cars after collision is 1.785 m/s
Answer:

West
Explanation:
m = Mass of car = 
t = Time = 9 seconds
u = Initial velocity = 30 m/s
v = Final velocity = 0
Impulse is given by

The magnitude of the total impulse applied to the car to bring it to rest is
.
The direction is towards west as the sign is negative.
We will convert the 1dm3 in terms of cm3 as follows:
1dm^3 = (10 cm)^3
= 1000 cm^3
The mass of platinum is equal to 900 lb.
Then we will convert the mass in terms of grams as follows:
1 lb = 453.6 g
900 = 900 x 453.6 g
= 408240 g
Then density of platinum is equal to 21.4 g/cm^3
We will calculate the volume of platinum in mass 408240 g as follows:
Volume of platinum = mass of platinum / density of platinum
= 408240 g / 21.4 g/cm^3
= 19076.6 cm^3
The total volume of platinum is 19076.6 cm^3
The volume of platinum in 1 L bar is 1000cm^3
So, to calculate the number of bars we will use the formula as follows;
Number of bars = volume of platinum available / volume of platinum required in 1 L bar
= 19076.6 cm^3 / 1000 cm^3
= 19
So, the number of bars are 19.