An electron is negatively charged.
Answer:
0.36 kg-m/s
Explanation:
Given that,
Mass of a ball, m = 0.06 kg
Initial velocity of the ball, u = 20 m/s
Final velocity of the ball, v = 26 m/s
We need to find the change in momentum of the tennis ball. It is equal to the final momentum minus initial momentum

So, the change in momentum of the ball is 0.36 kg-m/s.
<u>Answer</u>
8. 2 Hz
9. 0.5 seconds
10. 20 cm
<u>Explanation</u>
<u>Q 8</u>
Frequency is the number of oscillation in a unit time. It is the rate at which something repeats itself in a second.
In this case, the spring bob up and down 2 times per second.
∴ Frequency = 2 Hz
<u>Q 9</u>
Period is the time taken to complete one oscillation.
2 oscillations takes 1 second
1 oscillation = 1/2 seconds.
∴ Period = 0.5 seconds
<u>Q 10</u>
Amplitude is the the maximum displacement of the spring.
In this case the spring bob up 20 cm. This is it's displacement.
∴ Amplitude = 20 cm
Answer:
1. 3 m
2. 27 s
Explanation:
1. "A car traveling at +33 m/s sees a red light and has to stop. If the driver can accelerate at -5.5 m/s², how far does it travel?"
Given:
v₀ = 33 m/s
v = 0 m/s
a = -5.5 m/s²
Unknown: Δx
To determine the equation you need, look for which variable you don't have and aren't solving for. In this case, we aren't given time and aren't solving for time. So look for an equation that doesn't have t in it.
Equation: v² = v₀² + 2aΔx
Substitute and solve:
(0 m/s)² = (33 m/s)² + 2(-5.5 m/s²) Δx
Δx = 3 m
2. "A plane starting from rest at one end of a runway accelerates at 4.8 m/s² for 1800 m. How long did it take to accelerate?"
Given:
v₀ = 0 m/s
a = 4.8 m/s²
Δx = 1800 m
Unknown: t
Equation: Δx = v₀ t + ½ a t²
Substitute and solve:
1800 m = (0 m/s) t + ½ (4.8 m/s²) t²
t ≈ 27 s
a . true hardness and density are physical properties