Explanation:
hopefully that makes sense. the position doesn't change over the 5 seconds, meaning it's stopped but time still continues. then when the slope is negative this shows the bear's position becoming negative (backing up, changing direction).
Answer:
To calculate anything - speed, acceleration, all that - we need <em>data</em>. The more data we have, and the more accurate that data is, the more accurate our calculations will be. To collect that data, we need to <em>measure </em>it somehow. To measure anything, we need tools and a method. Speed is a measure of distance over time, so we'll need tools for measuring <em>time </em>and <em>distance</em>, and a method for measuring each.
Conveniently, the lamp posts in this problem are equally spaced, and we can treat that spacing as our measuring stick. To measure speed, we'll need to bring time in somehow too, and that's where the stopwatch comes in. A good method might go like this:
- Press start on the stopwatch right as you pass a lamp post
- Each time you pass another lamp post, press the lap button on the stopwatch
- Press stop after however many lamp posts you'd like, making sure to hit stop right as you pass the last lamp post
- Record your data
- Calculate the time intervals for passing each lamp post using the lap data
- Calculate the average of all those invervals and divide by 40 m - this will give you an approximate average speed
Of course, you'll never find an *exact* amount, but the more data points you have, the better your approximation will become.
Answer: a) 8.9km/s b) 4.05 x 10^-25 kg
Explanation:
a)
To find the velocity,
V = E/B plug in the numbers we get
V = 1.6kV/m / 0.18 T = 8.9 km/s
b)
To find the ion mass,
m = erB^2/E = 0.125 m x 1.6x10^-19 x (0.18)^2 / ( 1.6 x 10 ^ 3 V/m ) = 4.05 x 10 ^ -25 kg
Answer:
The net torque is 0.0372 N m.
Explanation:
A rotational body with constant angular acceleration satisfies the kinematic equation:
(1)
with ω the final angular velocity, ωo the initial angular velocity, α the constant angular acceleration and Δθ the angular displacement (the revolutions the sphere does). To find the angular acceleration we solve (1) for α:
Because the sphere stops the final angular velocity is zero, it's important all quantities in the SI so 2.40 rev/s = 15.1 rad/s and 18.2 rev = 114.3 rad, then:
The negative sign indicates the sphere is slowing down as we expected.
Now with the angular acceleration we can use Newton's second law:
(2)
with ∑τ the net torque and I the moment of inertia of the sphere, for a sphere that rotates about an axle through its center its moment of inertia is:
With M the mass of the sphere an R its radius, then:
Then (2) is:
