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
Answer:
1.78 J
Explanation:
Find the spring coefficient using Hooke's law:
F = k Δx
23 N = k (0.20 m − 0.14 m)
k = 383.33 N/m
The work is the change in energy:
W = PE₂ − PE₁
W = ½ kx₂² − ½ kx₁²
W = ½ k (x₂² − x₁²)
W = ½ (383.33 N/m) ((0.17 m)² − (0.14 m)²)
W = 1.78 J
The power of batteries in a circuit. The key functions of a battery and bulb in a circuit are explained. A battery is a source of energy which provides a push - a voltage - of energy to get the current flowing in a circuit. A bulb uses the electrical energy provided by the battery, but does not use current.
HOPE IT HELPS YOU OUT!
Answer:
a)
, b) 
Explanation:
a) The acceleration due to gravity inside the planet is:





b) The acceleration at the surface of the planet is:

assuming north-south along the Y-axis and east-west along the X-axis
X = total X-displacement
from the graph , total displacement along X-direction is given as
X = 0 - 20 + 60 Cos45 + 0
X = 42.42 - 20
X = 22.42 m
Y = total Y- displacement
from the graph , total displacement along Y-direction is given as
Y = 40 + 0 + 60 Sin45 + 50
Y = 90 + 42.42
Y = 132.42 m
magnitude of the net displacement vector using Pythagorean theorem is given as
magnitude : Sqrt(X² + Y²) = Sqrt(22.42² + 132.42²) = 134.31 m
Direction : tan⁻¹(Y/X) = tan⁻¹(132.42/22.42) = 80.4 deg north of east