(2nd variant, 7kg is 3 times faster than 21kg)
Answer:
Use the range formula - R = V^2 sin 2θ / g
A: R = V^2 sin 80 / g = .985 V^2 / g
B: R = V^2 sin 100 / g = .985 V^2 / g
It is the ratio of distance an object moves to the amount of time needed to travel the distance.
Option b.
Answer:
3.45×10⁻⁴mm (or 0.000345mm)
Explanation:
Use a method called dimensional analysis here. It involves a chain of conversions, so we'll need some conversions to work with.
- 1nm = 1×10⁻⁹m
- 1mm = 1×10⁻³m
- 345nm; which is given
If you knew the conversion from nanometers to millimeters then you could just do it in one step. But I don't, so I won't. Anyways, you put the conversions into fraction form like so:
And then orient them in a way where multiplying the two (or more in other instances) gives you the units you want. In this cas it's millimeters so you'll have:
(345nm)•(1×10⁻⁹m/1nm)•(1mm/1×10⁻³m)
Notice how all the units reduce except for mm. From here you just multiply across and should get 345×10⁻⁶mm which simplifies to 3.45×10⁻⁴mm.