Question

9 jill went to the store with her mom. after they loaded the groceries into the car, her mom gave her the cart and asked her to put the cart in the return cradle. when jill pushed the cart, she noticed that it went a lot farther than when she was in the store. this happened because
a. they were outside
b. the mass decreased because there were no groceries in it
c. the mass increased because of the friction
d. there was no change, jill got stronger.

1. what is the velocity of a plane that traveled 3,000 km from new york to california in 5.0 hours?

a. 600 km/h
b. 15,000 km/h west
c. 600 km/h west
d. 15,000 km/h

using the image complete the questions

1. these students are playing tug of war during field day. explain if it is a balanced or unbalanced force and how you know.

1. what is the net force and in which direction would the force be moving if needed?

Explanation:

Question 9

To determine why Jill's cart moved farther outside, we analyze the options:

• Option a: Being outside doesn't directly affect the cart's motion distance related to Jill's push. Eliminate.
• Option b: When the groceries were removed, the cart's mass decreased. According to Newton's second law (\(F = ma\)), with the same force (Jill's push), less mass means greater acceleration, so the cart moves farther. This makes sense.
• Option c: Friction doesn't increase mass. Mass is an intrinsic property (here, related to the cart's load). Eliminate.
• Option d: Jill's strength isn't stated to change, and the key factor is the cart's mass. Eliminate.

Step1: Recall velocity formula

Velocity is a vector quantity, so it needs magnitude and direction. The formula for average velocity (assuming constant speed) is \(v=\frac{d}{t}\), but we also need direction (New York to California is westward).
Wait, the problem seems to have a missing time? Wait, maybe a typo, but looking at options, let's assume time is 5 hours (since \(3000\div5 = 600\)). So magnitude is \(600\) km/h, direction west.

Step2: Analyze options

• Option a: No direction, velocity needs direction. Eliminate.
• Option b: 15,000 km/h is wrong (3000/t would be 600 if t=5). Eliminate.
• Option c: 600 km/h west (magnitude and direction, correct if time is 5h).
• Option d: No direction, and wrong magnitude. Eliminate.

For a balanced force, net force is zero (forces are equal and opposite). Here, left force is 400 N, right force is 300 N. Since \(400
eq300\), the forces are unbalanced. So it's unbalanced because the magnitudes of the forces (400 N left, 300 N right) are not equal, so net force is not zero.

Answer:

b. The mass decreased because there were no groceries in it

Question 10