Answer:
1.97J
Explanation:
Given parameters:
Mass of the groceries = 7kg
velocity of the bag = 75cm/s
Unknown:
Work done to move the bag = ?
Solution:
Work done is the force applied to move a body through a distance in a specific direction:
Work done = Force x distance
In this case, the work done is the kinetic energy applied in pulling the bag.
Kinetic energy is the energy in motion of a body.
Work done = kinetic energy =
where m is the mass
v is the velocity
Now, convert the velocity from cm/s to m/s
100cm = 1m
75 x = 0.75m/s
Work done = x 7 x 0.75² = 1.97J
Fg = m • g so 60kg • 9.8 m/s•s = 588 N
Answer:
42.11 years old
Explanation:
Given that:
In 2000, a 20-year-old astronaut left Earth to explore the galaxy; her spaceship travels at 2.5 x 10^8 m/s. She returns in 2040
To find her age we use:
Δtm is time interval for the observer stationary relative to the sequence of
events = 2040 - 2000 = 40 years
Δts is is the time interval for an observer moving with a speed v relative to the sequence of event
v = velocity = 2.5 x 10^8 m/s
c = speed of light = 3 x 10^8 m/s
Here age in 2000 is 20 year, therefore when she appear she would be 20 year + 22.11 year = 42.11 years old
Animals have more or multiple vacuoles while plant have larger ones