A 10 kg block is pushed with a constant horizontal force of 20 N against a constant horizontal frictional force of 10 N. What is the acceleration of the block?
1. 2 m/s2
2.5 m/s2
3. Zero
4. None of these
5. 1 m/s2
6. 10 m/s2
7. Insufficient information is provided.

Answer: it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.explanation:   we have equation of motion ,where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.average velocity = displacement/ time taken.average velocity = 10.69 miles/hr = 10.69*1.6*1000/(60*60) = 4.75 m/s4.75 = s/ts = 4. 1we also have acceleration = 2.18 m/s², initial velocity = 0 m/sso it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.