In which activity is no work done? a. pushing a shopping cart b. climbing stairs c. holding a brick d. lifting a book

Awind turbine is initially spinning at a constant angular speed. as the wind's strength gradually increases, the turbine experiences a constant angular acceleration 0.173 rad/s2. after making 2870 revolutions, its angular speed is 132 rad/s. (a) what is the initial angular velocity of the turbine? (b) how much time elapses while the turbine is speeding up?

What is the measure of a change in an objects velocity?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.