After a while, the car started to go around a long bend, still maintaining its constant speed of 55 miles per hour. is there a net (unbalanced) force acting on the car? 1. no; the speed of the car does not change. 2. cannot be determined 3. no; the velocity of the car does not change. 4. yes; its direction is not the same as the velocity. 5. yes; its direction is the same as the velocity.

4) True. The change of direction needs an unbalanced force

Explanation:

Let us propose the resolution of the problem using Newton's second law.

    F = m a

As the car is spinning the acceleration is centripetal

    a = v2.r

    F = m v2 / r

We can see that as the velocity of a vector even if its module does not change, the change of direction requires an external force.

Now we can analyze the statement if they are true or false

1) and 3) False, even when the speed changes, the direction changes

2) False with the speed change can be determined

4) True. The change of direction needs an unbalanced force

5) False are different things. the direction is where it is going and the speed is the magnitude of the vector

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.