Answer:
Explanation:
When an unbalanced force acts on an object, the object accelerates. We can immediately rule out B and D, as friction changes based on the material and by applying a force the net force can’t be zero. It can be easy to say that the object will speed up after the force is applied (and it often does!), but take a braking car, for example. An external force of friction is applied to the brakes, causing an acceleration but in such a fashion that the car slows down. So, although an object can speed up after a force is applied, it isn’t always guaranteed.
Hope this helps!
Answer: 1.38 m/s to the right.
Explanation: We can solve this problem using the principle of conservation of momentum. The momentum of an object is defined as the product of its mass and velocity, and the total momentum of a closed system is conserved, meaning that the total momentum before a collision is equal to the total momentum after the collision.Let the initial velocity of the dart be v, and let the final velocity of the dart and the block be vf. The momentum of the dart before the collision is given by p = mv, where m is the mass of the dart. The momentum of the dart and block after the collision is given by (m + M)vf, where M is the mass of the block.Using the principle of conservation of momentum, we have:p = (m + M)vfSubstituting the given values, we get:0.012 kg v = (0.012 kg + 0.2 kg) 0.78 m/sSimplifying, we get:v = (0.212 kg) (0.78 m/s) / 0.012 kgv ≈ 1.38 m/sTherefore, the velocity of the dart just before it hits the block is approximately 1.38 m/s to the right.
B Sam and Rachel pushed, but they could do no work on the car. ????
Answer:
6,653.34 J
Explanation:
Kinetic energy can be found using the following formula.
where m is the mass in kilograms and v is the velocity in m/s.
The object is 108 kilograms and is moving at a speed of 11.1 m/s. Therefore, the mass is 108 kg and the velocity is 11.1 m/s.
m=108 kg
v=11.1 m/s
Substitute these values into the formula.
Evaluate the exponent first. 11.1^2 is the same as 11.1*1.11, which is equal to 123.21
Multiply 108 and 123.21
Multiply 1/2 and 13306.68
The kinetic energy of the object is 6,653.34 Joules (kg m2/s^2)