用力(yòng lì) - to exert force, hard, with effort in Mandarin

用力 (yòng lì) is physical effort. It goes in front of another verb and tells you how the action was done: 用力推 (push hard), 用力拉 (pull hard), 用力握 (grip tightly). On its own it is an instruction shouted at somebody shifting a wardrobe.

Keep it well clear of 努力 (nǔ lì), which is effort of the studying and working kind. 努力学习 is working hard at your books; 用力学习 would suggest you are physically wrestling the textbook. English "try hard" splits across the two in Chinese and the split is by muscle versus perseverance.

Because it is a verb-object pair, things can slot between the halves: 用点力 (put a bit of force in) and 用了很大的力 (used a great deal of force) are both normal. That flexibility is the mark of a separable compound, and 用力 is one.