Answer:
The toy car
Explanation:
the real car is parked so yeah but maybe in some way technically the real car has more "momentum"
The total amount of energy always stays the same because of the law of conservation of energy, meaning that there is always the same amount of energy, it just gets turned into different forms like potential energy, kinetic energy, sound, thermal, etc.
Answer:
The magnitude of the tension on the ends of the clothesline is 41.85 N.
Explanation:
Given that,
Poles = 2
Distance = 16 m
Mass = 3 kg
Sags distance = 3 m
We need to calculate the angle made with vertical by mass
Using formula of angle



We need to calculate the magnitude of the tension on the ends of the clothesline
Using formula of tension

Put the value into the formula


Hence, The magnitude of the tension on the ends of the clothesline is 41.85 N.
Answer:
The car stops in 7.78s and does not spare the child.
Explanation:
In order to know if the car stops before the distance to the child, you take into account the following equation:
(1)
vo: initial speed of the car = 45km/h
a: deceleration of the car = 2 m/s^2
t: time
xo: initial distance to the child = 25m
x: final distance to the child = 0m
It is necessary that the solution of the equation (1) for time t are real.
You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:


You take the first value t1 because it has physical meaning.
The solution for t is real, then, the car stops in 7.78s and does not spare the child.
Answer:

Explanation:
By energy conservation we know that spring energy is converted into kinetic energy of the block
so we will have

so we will have

now we will have same thing for another mass 4m which moves out with speed 5v
so we have

now from above two equations we have

so we have
