A child does 350 J of work while pulling a box from the ground up to his tree house at a steady speed with a light rope. The tree house is above the ground. What is the mass of the box?
A) 8.9 kg
B) 5.3 kg
C) 6.7 kg
D) 8.0 kg
Question 2
Which of the following statements about spherical mirrors is correct? (There could be more than one correct choice.)
A) A concave mirror always produces a real image.
B) A convex mirror always produces a virtual image.
C) A concave mirror always produces a virtual image.
D) A convex mirror always produces a real image.
E) A convex mirror always produces an upright image.
Ernst Haeckel's Tree of Life (1879)
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