How are electromagnetic waves different from mechanical waves? Question 1 options:

Electromagnetic waves can travel through empty space; mechanical waves can not

Electromagnetic waves travel through water; mechanical waves can only travel through solid matter

Electromagnetic waves are long chains of vibrating molecules; mechanical waves aren't

Electromagnetic waves need a medium to travel through; mechanical waves do not

Electromagnetic waves can travel through empty space; mechanical waves can not  

Explanation:

The salient differences between electromagnetic waves and mechanical waves is that electromagnetic waves can travel through empty spaces but mechanical waves cannot.

Mechanical waves always requires a material medium for their propagation. No known mechanical waves can pass through an empty vacuum.

Electromagnetic waves on the other hand can pass through vacuum. They do not require a material medium for propagation.

This makes them unlimited in their form and mode of propagation.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

2b2t

explanation:

2b2t