A man in a boat moving at constant speed of 60km/h relative to the shore throws an object in the forward direction with a speed of 30km/h. What is the speed of the object as measured by an observer at rest at the shore?

90km/hr

NILL

To determine the speed of the object as measured by an observer at rest on the shore, we need to consider the concept of relative velocity.

Relative velocity is the velocity of an object with respect to another object or a reference frame. In this scenario, the man on the boat is throwing the object, and we want to determine its speed as measured by an observer on the shore.

First, let's define the velocities involved:

- Velocity of the boat with respect to the shore (vbs) = 60 km/h
- Velocity of the object thrown forward with respect to the boat (vbo) = 30 km/h

Now, to calculate the speed of the object as measured by an observer at rest on the shore, we need to add the velocities of the boat and the object:

Speed of the object as measured by the observer at the shore = Velocity of the boat with respect to the shore + Velocity of the object thrown forward with respect to the boat

Speed of the object as measured by the observer at the shore = 60 km/h + 30 km/h = 90 km/h

So, the speed of the object as measured by an observer at rest on the shore is 90 km/h.