A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the 50 N force? A. 100 J
B. 10 J
C. 50 J
D. 200 J

Match the following items. match the items in the left column to the items in the right column. 1. 1/1,000 precision 2. uncertainty value of measurement milli- 3. 1,000 accuracy 4. instrument to measure volume balance 5. degree of exactness of a measurement centi- 6. instrument to measure mass graduated cylinder 7. correctness of a measurement ± value 8. 1/100 kilo-