Answer:
B
8.5 km/h east
Explanation:
Relative velocity= Va -Vb
=10-1.5
=8.5 km/h east
The initial mechanical energy is the potential energy (PE) which can be solved through the equation,
PE = mgh = (40 kg)(9.8 m/s²)(12 m) = 4,704 J
The energy at the bottom is the kinetic energy and can be calculated through the equation,
KE = 0.5mv² = (0.5)(40 kg)(10 m/s)² = 2000 J
Therefore, she lost 2,704 J of energy due to friction
1). The little projectile is affected by friction all the way through the block.
Friction robs some kinetic energy.
2). The block is affected by friction as it scrapes along the top of the post.
Friction robs some kinetic energy.
3). The block is also affected by friction with the air (air resistance) as it
falls to the ground. Friction robs some kinetic energy.
Answer:
The time taken by the rotating object to speed up from 15.0 s to 33.3 rad/s is 5.30 seconds.
Explanation:
It is given that,
Initial angular speed of the object,
Final angular speed of the object,
Angular acceleration of the object,
Angular acceleration of an object is object is defined as the change in angular velocity per unit time. It is given by :
t = 5.30 seconds
So, the time taken by the rotating object to speed up from 15.0 s to 33.3 rad/s is 5.30 seconds. Hence, this is the required solution.