1)Two balls having the same mass of 1 kg roll toward each other, each moving at the same speed of 1 m/s. What is the combinded momentum?
Would it be 0 kg m/s
2)A 30 kg girl and a 25kg boy face each other on friction free roller blades. The girl pushes the boy who moves away at 1 m/s. The girls speed is?
Would it be .45
3)The power extended when a 10 N barbell is raised 2.0 m in 2 s is _____ watts
would it be 40?
4)Car A travels for times as fast as Car B. When braking to a stop Car A skids____ times as far as car B.
16?
(1) yes
(2) no. 30*Vgirl = -25*Vboy
Solve for Vgirl when Vboy = 1
(3) no. DIVIDE the work by the time
(4) yes. 4^2 = 16 Do you know why the skid is proportional to the square of speed? It has to do with kinetic energy
would it be 55
1) The combined momentum of the two balls can be found by adding their individual momenta. Momentum is defined as the product of an object's mass and velocity.
The momentum of each ball is given by mass multiplied by velocity, so for each ball, the momentum is 1 kg * 1 m/s = 1 kg m/s.
To find the combined momentum, simply add the individual momenta of the two balls: 1 kg m/s + 1 kg m/s = 2 kg m/s. Therefore, the combined momentum is 2 kg m/s, not 0 kg m/s.
2) In this scenario, we can use the principle of conservation of momentum. According to this principle, the total momentum before an event is equal to the total momentum after the event, provided there are no external forces acting on the system.
Before the girl pushes the boy, the total momentum is 0 kg m/s since they are stationary. After the girl pushes the boy, they move away in opposite directions. Let the girl's speed be represented by Vgirl and the boy's speed by Vboy. According to conservation of momentum, the total final momentum is also 0 kg m/s.
We can use the equation: mass1 * velocity1 + mass2 * velocity2 = 0 kg m/s.
Substituting the values given: 30 kg * Vgirl + (-25 kg * 1 m/s) = 0 kg m/s.
Simplifying the equation: 30 kg * Vgirl = 25 kg * 1 m/s.
Solving for Vgirl: Vgirl = (25 kg * 1 m/s) / 30 kg = 0.833 m/s.
Therefore, the girl's speed is approximately 0.833 m/s, not 0.45 m/s.
3) Power is defined as the amount of work done per unit time. Work is calculated as the product of force and distance. In this case, the force exerted is 10 N and the distance moved is 2.0 m. The time taken is 2 seconds.
The work done can be calculated as: work = force * distance = 10 N * 2.0 m = 20 N·m (also known as Joules).
To find the power, simply divide the work done by the time taken: power = work / time = 20 N·m / 2 s = 10 watts.
Therefore, the power extended when a 10 N barbell is raised 2.0 m in 2 seconds is 10 watts, not 40 watts.
4) When a car brakes to a stop, the distance it skids is proportional to the square of its initial velocity (speed). Let the initial speed of Car B be V, then the initial speed of Car A is 4V (four times as fast).
The distance skidded is directly proportional to the square of the speed change. So, the skid distance for Car B is V^2, and for Car A it is (4V)^2 = 16V^2.
Therefore, Car A skids 16 times as far as Car B, not 4 times as far.