Answer:
m = 0.01 kg
Explanation:
Given that,
Momentum of the marble, p = 0.15 kg-m/s
Speed of the marble, v = 15 m/s
We need to find its mass. We know that,
Momentum, p = mv
Where
m is the mass
![m=\dfrac{p}{v}\\\\m=\dfrac{0.15}{15}\\\\m=0.01\ kg](https://tex.z-dn.net/?f=m%3D%5Cdfrac%7Bp%7D%7Bv%7D%5C%5C%5C%5Cm%3D%5Cdfrac%7B0.15%7D%7B15%7D%5C%5C%5C%5Cm%3D0.01%5C%20kg)
So, the mass of the marble is equal to 0.01 kg.
the upward force is from the table and the downward is from gravity they are equal in force so the box doesn't fly up or sink down
Answer: c. they will hit the ground at the same time
Explanation:
The volume of both objects is almost the same, so the force of friction will be the same in each one, so we can discard it.
Now, when yo drop an object, the acceleration of the object is always g = 9.8m/s^2 downwards, independent of the mass of the object.
So if you drop two objects with the same volume but different mass, because the acceleration is the same for both of them, they will hit the ground at the same time, this means that the density of the object has no impact in how much time the object needs to reach the floor.
So the correct option is c
The sprinter’s average acceleration is 1.98 m/s²
The given parameters;
- initial velocity of the sprinter, u = 18 km/h
- final velocity of the sprinter, v = 27 km/h
- time of motion of the sprinter, t = 3.5 x 10⁻⁴ h
Convert the velocity of the sprinter to m/s;
![initial \ velocity, u = 18 \frac{km}{h} \times \frac{1000 \ m}{1 \ km} \times \frac{1 \ h}{3600 \ s} = 5 \ m/s\\\\final \ velocity, v =27 \frac{km}{h} \times \frac{1000 \ m}{1 \ km} \times \frac{1 \ h}{3600 \ s} = 7.5 \ m/s\\\\](https://tex.z-dn.net/?f=initial%20%5C%20velocity%2C%20u%20%3D%2018%20%5Cfrac%7Bkm%7D%7Bh%7D%20%5Ctimes%20%5Cfrac%7B1000%20%5C%20m%7D%7B1%20%5C%20km%7D%20%5Ctimes%20%5Cfrac%7B1%20%5C%20h%7D%7B3600%20%5C%20s%7D%20%3D%205%20%5C%20m%2Fs%5C%5C%5C%5Cfinal%20%5C%20velocity%2C%20v%20%3D27%20%5Cfrac%7Bkm%7D%7Bh%7D%20%5Ctimes%20%5Cfrac%7B1000%20%5C%20m%7D%7B1%20%5C%20km%7D%20%5Ctimes%20%5Cfrac%7B1%20%5C%20h%7D%7B3600%20%5C%20s%7D%20%3D%207.5%20%5C%20m%2Fs%5C%5C%5C%5C)
The time of motion is seconds;
![t = 3.5 \times 10^{-4} \ h \times \frac{3600 \ s}{1 \ h} = 1.26 \ s](https://tex.z-dn.net/?f=t%20%3D%203.5%20%5Ctimes%2010%5E%7B-4%7D%20%5C%20h%20%5Ctimes%20%5Cfrac%7B3600%20%5C%20s%7D%7B1%20%5C%20h%7D%20%3D%201.26%20%5C%20s)
The sprinter’s average acceleration is calculated as follows;
![a = \frac{v- u}{t} \\\\a = \frac{7.5 \ m/s \ - \ 5 \ m/s}{1.26 \ s} \\\\a = 1.98 \ m/s^2](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7Bv-%20u%7D%7Bt%7D%20%5C%5C%5C%5Ca%20%3D%20%5Cfrac%7B7.5%20%5C%20m%2Fs%20%5C%20-%20%5C%205%20%5C%20m%2Fs%7D%7B1.26%20%5C%20s%7D%20%5C%5C%5C%5Ca%20%3D%201.98%20%5C%20m%2Fs%5E2)
Thus, the sprinter’s average acceleration is 1.98 m/s²
Learn more here:brainly.com/question/17280180
Work done = 0.5*m*[(v2)^2 - (v1)^2]
where m is mass,
v2 and v1 are the velocities.
Given that m = 1.50 x 10^3 kg, v2 = -15 m/s (decelerates), v1 = 25 kg,
Work done = 0.5 * 1.50 x 10^3 * ((-15)^2 - 25^2) = 3 x 10^5 joules
Just ignore the negative value for the final result because work is a scalar quantity.