The planet closest to the sun; Mercury.
It magnifies light received from distant objects.
Answer:
v = 2.18m/s
Explanation:
In order to calculate the speed of Betty and her dog you take into account the law of momentum conservation. The total momentum before Betty catches her dog must be equal to the total momentum after.
Then you have:
(1)
M: mass Betty = 40kg
m: mass of the dog = 15kg
v1o: initial speed of Betty = 3.0m/s
v2o: initial speed of the dog = 0 m/s
v: speed of both Betty and her dog = ?
You solve the equation (1) for v:

The speed fo both Betty and her dog is 2.18m/s
It would take 30 minutes
You would do 15.0 divided by 0.5
The runner has initial velocity vector

and acceleration vector

so that her velocity at time
is

She runs directly east when the vertical component of
is 0:

It's not clear what you're supposed to find at this particular time... possibly her position vector? In that case, assuming she starts at the origin, her position at time
would be

so that after 10.4 s, her position would be

which is 19.9 m away from her starting position.