A shopping cart that starts from rest, is accelerated for 4 s, moves at constant velocity for 4 s, and is decelerated for 4s until returning to rest, has an average acceleration of 0 m/s².
A shopper is pushing a cart down a grocery store aisle. The movement of the cart is:
- It starts from rest.
- From t = 0 s to t = 4.0 s it is accelerated with a constant force.
- From t = 4 s to t = 8.0 s it receives just enough force to balance the friction on the cart.
- From t = 8 s to t = 12 s it is decelerated until it comes to rest.
All in all, at the initial time (t = 0 s), the velocity is 0 m/s (rest) and at the final time (t = 12 s) the velocity is 0 m/s as well (rest). The average acceleration in that period is:
A shopping cart that starts from rest, is accelerated for 4 s, moves at constant velocity for 4 s, and is decelerated for 4s until returning to rest, has an average acceleration of 0 m/s².
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Answer:
81.3ohms
Explanation:
Resistance is known to provide opposition to the flow of electric current in an electric circuit.
Power dissipated by the computer is expressed as;
Power = current (I) × Voltage(V)
P = IV... (1)
Note that from ohms law, V = IR
I = V/R ... (2)
Substituting equation 2 into 1, we will have;
P = (V/R)×V
P = V²/R.. (3)
Given source voltage = 100V, Power dissipated = 123W
To get resistance R of the computer, we will substitute the given value into equation 3 to have
123 = 100²/R
R = 100²/123
R = 10,000/123
R = 81.3ohms
The resistance of the computer is 81.3ohms
Answer:
3
Explanation:
The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.
This can be rewritten as follows:
where
m(t) is the mass of the sample at time t
m0 is the original mass of the sample
n is the number of half-lives that passed
We see that if we take n=3, the amount of original sample left is
So 3 (3 half-lives) is the correct answer.
Answer:
1) Motion of air mass moving from equator northward (closer to earth axis)
2) Motion of object in orbit
3) Collision of 2 objects
4) Skater changing rotation by extension of arms
5) Motion of rocket due to velocity of expelled gas
